Brigham Young University BYU ScholarsArchive
Theses and Dissertations
1976-08-01
A phylogenetic study of the suffrutescent shrubs in the genus atriplex
C. Lorenzo Pope Brigham Young University - Provo
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BYU ScholarsArchive Citation Pope, C. Lorenzo, "A phylogenetic study of the suffrutescent shrubs in the genus atriplex" (1976). Theses and Dissertations. 7960. https://scholarsarchive.byu.edu/etd/7960
This Dissertation is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. A PHYLOGENETICSTUDY OF THE S0.1!1FR0TEBCENTSHRu:BS
IN THE GENUSATRIPLEX
A Dissertation Presented to the Department of Botany and Range Science
Brigham Young University
In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy
by c. Lorenzo Pope .August 1976
ACKNOWL.EDGMENTS
Special thanks are extended to the following who helped make this publication possible: Dr. Howard c. Stutz, chairman of the advisory committee, for his continued support in giving encouragement, stimulating ideas, and concepts; Dr. Kimball T. Harper, Dr. Stanley L. Welsh, and Dr. Fred G. White for serving on the advisory committee; A.H. Williams, Rice Researchers, Inc., Glenn, California, for extending released time from work; James c. Pope, myfather, and Leora and Kenneth Cropper, mother and father-in-law, for their constant encouragement and financial support. Financial assistance was provided by Brigham Young Univer- sity through teaching and research assistantships, research and tuition and fee fellowships, and an NDEATitle IV Fellowship. Research facilities, equipment, supplies, and travel were provided
by the Department of Botany and Range Science, Brigham Young University.
The patience of my wife, Nancy, during the research and writing of this dissertation, as well as her help in typing the manuscript, is gratefully acknowledged.
iii TABLEOF CQNTENTS
ACKNOWLEDGMENTS• • • • • • • • • • • • • • • • • • • • • • • iii LIST OF ILLUSTRATIONS•• • • • • • • • • • • • • • • • ••• V LIST OF TABLEB • • • • • • • • • • • • • • • • • • • • • • • ix Chapter I. INTRODUCTION• • • • • • • • • • • • • • • • • • • • • 1 II. MORPHOLOGICALSTUDIES • • • • • • • • • • • • • • • • 6 Materials and Methods Results and Discussion
III. CYTOLOGICALSTUDIES • • • • • • • • • • • • • • • • • 105 Materials and Methods Results and Discussion
IV. ECOLOGICALAND BIOGEOGRAPHIC.AL STUDIES • • • • • • • • 126 Materials and Methods Results and Discussion
V. PHENOLOGICALSTUDIES. • •••••••••••• • • • 163 Materials and Methods Results and Discussion
VI. GENEI'ICSTUDIES • • • • • • • • • • • • • • • • • • • 197 Materials and Methods Results and Discussion
VII. TAXONOMICSTUDIES • • • • • • • • • • • • • • • • • • 227 VIII. CONCLUSION.• • • • • • • • • • • • • • • • • • • • • 260 LIST OF REFERENCES• • • • • • • • • • • • • • • • • • • • • 271 LIST OF ILLUSTRATIONS
Figure Page 1. Bar graphs of the averages of four fruit characters in diploid populations of Atriplex ••••••••• 50-51
2. NewmanKeul Multiple Range Test for two leaf characters from the!• ga.rdneri populations listed in Table 21 57 3. Phenogram of twenty-eight populations of Atriplex clustered by using eighteen leaf, fruit, and habit characters • • • • • • • • • • • • • • • • • • • • • 61-62 4. The cluster analysis phenogram of 56 plants from eight widely scattered populations of Atriplex •••••• 63-64 5. Phenogram of twenty-eight populations of Atriplex clustered by using leaf characters. • • • • • • • • 65 6. Phenogram of twenty-eight populations of Atriplex clustered by using fruit characters •••••••• 67-68 7. Phenogram of twenty-eight populations of Atriplex clustered as to the discriminant analysis results in Table 24 ••••••••• • • • • • • • • • • • 82-83 8. Two dimensional picture of the dispersion of the canonical variables of the following sp_$c.ies: (A)!• ga.rdneri (2n=36), (B) !• falcata, (c) !• tridentata, (D) A. coITGta, (E) !• welshii, (F) !• ·cuneata (2n=36~) !• cuneata ssp. intro- =)(~).!: ~~e:t: ~2~~8~,.8:1d.(:).!: ?;~e~i. 84-85 9. Two-dimensional diagram of the dispersion of the canonical variables of the narrow leaf species in the!• gardneri complex. • • • • • • • • • • • • 86 10. Two-dimensional dispersion of the canonical variables of two diploid species and their tetraploids. • • • 88 11. Two-dimensional diagram of the dispersion of the canonical variables of seven populations of A_; ga.rdneri • • • • • • • • • • • • • • • • • • • • • • 92-93
V Figure Page
12. Two-dimensional diagram of the dispersion of the canonical variables of five populations of A• cuneata ••• • • • • • • • • • • • • • • • • • 96-97 13. Two-dimensional diagram of the dispersion of the canonical variables of three·popula.tions of A• corrue;ata ••••••••••••••••••• 101-102 14-15. Polysomaty in one root-tip of A•falcata from northwest of the Desert Mountains in Utah. • • 112 16-19. Cytological micrographs of chromosomes of A• falcata (2D=18) ••• • • • • • • • • • • • • • 114 20-21. Cytological micrographs of chromosomes·or A•· welshii (2n=18) ••• • • • • • • • • • • • • • 115 22-24. Cytological micrographs of chromosomes of A• cuneata ssp. introgressa • • • • • • • • • • • 116 25-26. Cytological micrographs of chromosomes of the diploid A. cuneata (2n:=18) • • • • • • • • • • 117 27-28. Cytological micrographs of chromosomes of the tetraploid A• cuneata (2n=36) • • • • • • • • • 118 29-30. Cytological micrographs of chromosomes of A• corrugata (2n:=36). • • • • • • • • • • • • • • 119 31-32. Cytological microfaphs of chromosomes of A• gardneri (2n=36 •• • • • • • • • • • • • • • 120 33-34. Cytological micrographs of chromosomes of the diploid!.• gardneri (2n=18). • • • • • • • • • 121 35-38. Cytological micrographs of chromosomes of A• tridentata (2n=54) • • • • • • • • • • • • • • 122 39. The approximate geographic distribution of species in the A•,saraneri complex • • • • • • • • • • 131-132 40. Distribution map of A· corrugata • • • • • • • • 133-134'. 41. Distribution map of A• cuneata • • • • • • • • • 135-136 42. Distribution map of!.• tridentata. • • • • • • • 137-138 43. Distribution map of A•ga.rdneri • • • • • • • • • 139-140 vi Figure Pa.ge Distribution map of the diploid species,!• fa.lcata, A. welshii, · and A. cuneata sap. introgressa • • • • • • •-• • • • • • • • • • • • 141-142 45. Cluster analysis of 63 populations of Atriplex according to their environmental parameters. • • 15;-154 46. Cluster a.na.lysis of the Atriplex·species according to their edaphic factors • • • • • • • • • • • • 157 47. Edaphic parameters graphed a.gs.inst the species order from the cluster analysis program. • • • • • • • 158 48. Ranking of species by percent sand and percent fines 159
49. Ranking of species by :relative sodium concentrations as indicated by pH dilution series from calculated means • • • • • • • • • • • • • • • • • • • • • • 160 50. sta;ning patterns of excised seeds treated with 0.1 percent tetrazolium chloride •••••••••• 183 51. Hypocotyl elongation in five species of Atriplex 196 52-53. Habit of A. welshii and habitat of!• cuneata. ssp. intropssa. ••••••••••••••••••• 230 54-55. Fruits of!• cuneata ssp. introgressa and!• welshii 231 56. Fruit dmwings of!• welshii and!• ouneata ssp. introgressa • • • • • • • • • • • • • • • • • • • 232 57. Leaf drawings of!• welshii and!• cunea.ta. ssp. introgressa. • • • • • • • • • • • • • • • • • • • 233 58-59. Habitat of!• fa.lcata...... 236 60. Fruit drawings of!• fa.lcata •••••• •.... 237 61. Leaf dmwings of -A. falcata • • • • • • • • • • • • 238 62-63. Fruits of!• fa.lcata and!• tridenta.ta • • • • • • 239
64-65. Habit and habitat of!• tridentata • • • • • • • • 241 66. Fruit dmwings of!• tridentata. • • • • • • • • • 242 67. Leaf drawings of!• tridentata. • • • • • • • • • • 243
vii Figure Page 68-69. Habit and habitat of!• corruga.ta •••••••• • 245 70. Fruit and leaf drawings of!• corruga.ta. • • • • • 246 71-73. Fruits of!• corruga.ta, !• eerdneri, and!• ouneata 247 74-76. Habit and habitat of!• ga.rdneri • • • • • • • • • 250
77. Fruit drawings of!• gardneri • • • • • • • • • • 251 78. Leaf drawings of!• gardneri • • • • • • • • • • • 252
79-81. Habit and habitat of!• ouneata (2n=18) from near Bonanza, Utah. • • • • • • • • • • • • • • • • • 254 82. Fruit and leaf drawings of!• ouneata (2n=18). • • 255 83-84. Habit and habitat of!• ouneata. • • • • • • • • • 256 85. Fruit drawings of!• ouneata (2D=36) • • • • • • • 257 86. Leaf drawings of!• euneata (2n=36) •• • • • • • • 258
viii LIST OF TABLES
Table Page 1. Species included in the Atriplex ga.rdneri complex. • • 3 2. Populations in the!• ga.rdneri complex included in the studies of morphological variation • • • • • • • • • 7 3. Morphological characters which were statistically analyzed in selected populations of the!• ga.rdneri complex • • • • • • • • • • • • • • • • • • • • • • • 8 4. One-way analysis of variance of selected characteristics of male plants in three populations of Atriplex. • • 11 5. One-way analysis of variance of selected characteristics of female plants in three populations of Atriplex. • 12 6. One-way analysis of variance of selected characteristics of three populations of Atriplex (includes both sexes) 14 7. Multivariate analysis for bisexualism in morphological expressions of three populations of Atriplex • • • • 15
8. Multivariate analysis of fruit characteristics in ten plants of!• welshii •••••••••••••••• 17-18 9. Means of measurements of ha.bit, leaf, and fruit characters in!• gardneri populations •••••••• 20-21
10. Summary of ha.bit, leaf, and fruit character means in !• ga.rdneri populations. • • • • • • • • • • • • • • 22 11. Means of measurements of ha.bit, leaf, and fruit characters in!• tridentata populations. • • • • • • 23-24 12. Means of measurements of ha.bit, leaf, and fruit characters in!• corru,sata populations • • • • • • • 25-26 13. Means of measurements of ha.bit, leaf, and fruit characters in!• falcata populations • • • • • • • • 27-28 14. Means of measurements of ha.bit, leaf, and fruit characters in!• welshii populations • • • • • • • • 29-30 ix Table Page
15. Means of measurements·· of habit, leaf, and fruit characters in the!• cu:neata ssp. introgressa population •••••••••••••••••• • • • 31 16. Means 0£ measurements 0£ habit, lea£, and :fruit characters in diploid!• cuneata populations (2~18) 32-33 17. Means of measurements of habit, leaf, and fruit characters in tetraploid A. ouneata populations (~36) •••••••• : •••••••••• • • • 34-35 18. Summaryof means of measurements of habit, leaf, and fruit cha.ra.cters in eaoh species in the!~ gardneri complex • • • • • • • • • • •••••••••••• 37-39
19. Duncan's New Mtlltiple Range Test on all species in the Atriplex ga.rdneri complex ••••••••••• 40-48 20. Comparison of A. welshii and A. cuneata ssp. introg.ressa with respect tothe means of their morphological characters. • • • • • • • • • • • • • 53 21. Populations sampled for analysis of variance of characteristics of Atriplex in Wyoming, Montana, and Alberta, Canada • ••• • • • ••• • • • •. • 54 22. One-way analysis of variance of morphological measurements in!• ga.rdneri from Wyomingand northern Utah • • • • • • • • • • • • • • • • • • • 55-56 23. One-way analysis of variance of morphological measurements in different population combinations of !• gardneri • • • • • • • • • • • • • • • • • • • 58-59 24. A summary of discriminant analysis for nine species in the!• ga.rdneri complex ••••••••••••• 69 . 25. The number of plants which were classified into their respective species at steps nine and eighteen in the discriminant analysis·or all species in the·A. ga.rdneri complex •••••••••••••• - •••• 71-72 26. The number of plants which were classified into their respective species in each step of the first eight steps in the discriminant analysis or·a11 species in the!• ga.rdneri complex ••••••••• 73-80 27. The discriminant analysis s1.lJil1Dai'y·forseven populations of!• ga,rdneri. • • • • • • • • • • • • 89
X Table Page
28. The number of plants which were classified into their respective populations at steps seven and eighteen in the discriminant analysis of seven populations of!• gardneri • • • • • • • • • • • • • • •••••••• 90-91 29. The discriminant analysis summa.:cyfor!• cuneata. • • 94 30. The number of plants which were classified into their respective populations at steps £our, twelve, and eighteen in the discriminant analysis of five Utah populations of!• cuneata • • • • • • • • • • • • • 95
31. The discriminant analysis summary for!• corrugata.. 99 32. The number of plants which were classified into their respective populations at steps three, eight, twelve, and eighteen in the discriminant analysis of all populations of!• corrugata • • • • • • • • • • • • 100 33. The discriminant analysis summary for!• tridentata • 103 34. The number of plants which were classified into their respective populations at steps four, thirteen, and eighteen in the discriminant analysis of all populations of!• tridentata. • • • • • • • • • • • 104 35. Cytological analysis of the subshrubs in the genus Atriplex •••••••••••••••••••••• 107-110 36. Cytological summary of chromosomal races in the!• gardneri complex. • • • • • • • • • • • • • • • • • 113 37. Environmental parameters of each species in the ·Atriplex gardneri complex • • • • • • • • • • • • • 128 38. A species list of plants associated with the Atriplex gardneri complex. • • • • • • • • • • • • • • • • • 130 39. Soil analysis of soils occupied by the subshrubs of the genus Atriplex ••••••••••••••••• 144-149 40. Summary of the soil analysis of soils occupied by the subshrubs of the genus Atriplex • • • • • • • • 150 41. Class rating of soil characteristics as recorded in Table 39 • • • • • ••• • • • • ••••••• • • • 155 42. Calculated parameter means for each·species·from data recorded in Table 39. • • • • • • • • • • • • • • • 156
xi Table Page 43. Species list and number of sources included in the germination studies • • • • • • • • • • • • • • • • 164 Populations included in the phenologica.l study of seedling development· •••••• • • • •••• • • 168-169 45. Seed germination in four species of Atriplex: !• cunea.ta., !• · co;:rue;a.ta., !• fa.lea.ta., and !• tridentata ••••••••••••••••• • • • 170 46. Effects of washing and cold treatment on the germination of tln'ee species of Atriplex • • • • • 172 47. Anal.ysis of the seeds in· the germination experiment recorded in Table 45 • • • • • • • • • • • • • • • 173
48. Germination of the suf!'ru.tescent shrubs in the genus Atriplex • • • • • • • • • • • • • • • • • • • • • 175 49. Germination of excised seeds of!• eo;z;:rue;a.taafter scarification with sandpaper • • • • • • • • • • • 176 50. Seed fill in the suffrutescent shrubs in the genus Atriplex determined by x-ra.y photogt'S.phs and by cutting open • • • • • • • • • • • • • • • • • • • 178 51. Separation of filled fruits of Atriplex by flotation in 95% ethanol • • • • • • • • • • • • • • • • • • • • 180 52. Viability' of Atriplex seeds as determined by testing with tetrazolium chloride... • • • • • • • • • • 182 53. Potential seed germination of each species in the Atriplex gardneri complex as determined by seed fill and seed viability •• • •. •.... • • • • 184
54. Reduction in seed fill as indicated by the number of fully developed seed coats that lack endospem · and/or embryos • •·• ••••••••••••••• 186
55. Seed fill in diploid and tetra.ploid populations of certain Atriplex species •••••••• • •• • • 187 56. Reduction·in·seed·rill'as·a·resu.1t·or visible insect da.mage • ' ••••••••••••••••••••• 189 57. Inhibitory effects of Atriplex lea.chates on the germination of lettuce and radish seeds •••••• 191-192
xii Table Page
5a. Phenological observations in five species of Atriplex 194-195 59. Percent heritability estimates of leaf and fruit characters in!• falcata. • • • • • • • • • • • • • 200-201 60. Percent heritability estimates of leaf and fruit characters in!• welshii. • • • • • • • • • • • • • 202 61. Percent heritability estimates of leaf and fruit characters in!• cuneata ssp. introgressa • • • • • 203 62. Percent heritability estimates of leaf and fruit characters in!• cuneata (2:n;:18). • • • • • • • • • 204 63. Percent heritability estimates of leaf and fruit characters in!• cuneata (2n=36). • • • • • • • • • 205 64. Percent heritability estimates of leaf and fruit characters in!• gardneri • • • • • • • • • • • • • 206-207 65. Percent heritability estimates of leaf and fruit characters in!• tridentata • • • • • • • • • • • • 208-209 66. Percent heritability estimates of leaf and fruit characters in!• corruga.ta. • • • • • • • • • • • • 210 67. Summary of percent heritability estimates in species of Atriplex •••••••••••••••••••• 211-212 68. Rootsprouting and layering in species of the!• ga.rdneri complex. • • • • • • • • • • • • • • • • • 214 69. Sex ratio in the Atriplex gardneri complex. • • • • • 216 70. Frequency range in monoecious plants in species of the!• ga.rdneri complex • • • • • • • • • • • • • • 217 71. Sex ratios and descriptions of monoecious plants of selected populations from specJes in the A. ga.rdneri complex ••••••••••• 7 . .... 219-220 72. Seasonal sex patterns in a permanent plot of!• corruga.ta • • • • • • • • • • • • • • • • • • • • • 221 73. Species in the Atriplex ga.rdneri complex that hybridize with other Atriplex species • • • • • • • 224 74. Germination of seeds from·artificial hybrids produced by controlled crosses • • • • • • • • • • • • • • • 225
75. Percent seed fill in isolated female plants • • • • • 226 xiii CHAPrERI
INTRODUCTION
Atriplex, with about 220 species, is the largest and most
diversified genus in the family, Chenopodiaceae. It occupies much of the 41 million acres of salt desert shrub vegetation (Clapp, 1936) in the western United States. Widely distributed, these Atriplex plants furnish forage for livestock (sheep, cattle, and horses) and wildlife in all seasons; the perennial subshrubs are especially valuable in winter (Nelson, 1898; Smith, 1900; Nelson, 1904; McCreary, 1927; Dayton, 1931; Clarke, et al., 1943; Cook, et al., 1951; McLean, 1953; Stoddart and Smith, 1955; Hunt and Lang, 1957; Russey, 1967). The importance of Atriplex subshrubs is due to their abundance, accessibility, large volume of foliage, evergreen habit, high palatability, and high nutritive value. The nutritive value of several of the species is among the highest of all desert plants. Green samples were found to have 4.7 percent crude protein and dry samples as high as 16.56 percent (Knight, et al., 1905). In fact, McCreary (1927) showed that the leaves compare very favorably with the best alfalfa hay. Also, studies by Cook and Harris (1950) and Cook (1971) indicate that the nutrient content of all shrubs does not undergo as great a seasonal change as does that of forbs and grasses, and thus maintains high levels of protein, fat, calcium, and phosphorus.
1 2
This study is focused primarily upon certain Atriplex species growing in the Intermountain Begion of the United States. It is restricted to the shrubby species of Atriplex described by Hall and Clements (1923) as the perennial shrubs having herbaceous stems. They a.re a part of a small group of dioecious species which a.re intermediate between herbaceous and strictly shrubby forms. The species included are: J:..acanthocarpa, !,. obovata, !• corruga.ta, and!• nuttallii, which includes six subspecies, i.e.,!• typica, !• tridentata, !• gardneri, !• cuneata, !• buxifolia, and!• falcata. Most of the emphasis was given to the species in the proposed !• "nuttallii n group (!. ga.rdneri, !• tridentata, !• falcata, !• cuneata, and!• buxifolia) plus several other Atriplex species, i.e.,!• co:r;rugata, !• cuneata ssp. introgressa, and!• welshii. As pointed out by Hanson (1962), the original epithet of Atriplex nuttallii Watson includes the holotypes of both!• canescens (Pursh) and!• gardneri (Moq.). He therefore suggested that the name, 11nuttallii," is nomenclaturally superfluous and invalid and that members of this complex should be renamed, Atriplex W4Peri (Moq.). The nomenclature used in this thesis is that utilized by Hanson (1962), with a few modifications pointed out below (see Table 1). In response to Hanson's suggestion, this complex of species will hereafter be referred to as the Atriplex gardneri complex.
In reviewing the literature, it became quite obvious that taxonomic confusion exists in this complex, and clarification is certainly needed (see Russey, 1967; West and Ibrahim, 1968; 3
TABLE1. Species included in the Atriplex gardneri complex
Scientific name Commonname
!• acanthocarpa ((Torrey) Watson, 1894] Burscale !• bu:x:ifolia (Rydberg, 1912) !• corrugata (Watson, 1891) Matscale !.• cuneata (Nelson, 1902) Castle Valley clover !.• cuneata ssp. introgressa (Hanson, 1962) .!.• falcata [(Jones) Standl, 1916) .!.• ~a.rdneri f(Moq.) Dietr., 1852] Gardner saltbush .!.• obovata (Moq., 1840) Broad.scale (silver salt- bush)
.!.• tridentata (Kuntze, 1891) Three-toothed saltbush .!.• welshii (Hanson, 1962) 4 Nord, et al., 1969; Cook, 1971, Johnson, 1975). Most who have studied this group continue to use the taxonomic nomenclature, !• nuttallii, although their studies usually apply to only restricted populations or areas (McLean, 1953; Windle, 1960; Vosler, 1962; Russey, 1967; etc.). This has created a conglomerate of information which applies to the entire complex but .!l21to any one entity. It also makes a meaningful literature review very difficult. Taxonomic problems in Atriplex are most likely caused by a lack of distinguishing morphological characteristics between the species and to the phenotypic variation of those which are available. For example, all of the subspecies listed under!• nuttallii by Hall and Clements (1923), with the exception of!• falcata, are based upon characters that are not constant. It must be expected, therefore, that some specimens cannot be definitely clas- sified. At present, it is not clear whether this complex contains a few highly polymorphic species or a greater number of closely related ones.
Thus, the objective of this study was to investigate and hopefully clarify the taxonomic and phylogenetic relationships of these suffrutescent shrubs. Various representative populations, distributed throughout the Intermountain West, were selected for detailed analysis. These populations appeared to include all of the morphological variation present within the complex. Representative forms from each of the morphological entities were then analyzed morphologically, cytologically, ecologically, 5 phenologically, genetically, and taxonomically (see Chapters II through VII.). CHAPTERII
MORPHOLOGICALSTUDIES
Materials and Methods To investigate the morphological variation in the Atriplex ga.rdneri complex, several hundred populations were studied. Twenty- eight of these populations were analyzed in detail to determine the range of their morphological expressions. (See Table 2 for a list of populations.) The habit, leaf, and fruit characters of seven randomly collected plants of each population were analyzed. Five samples from each plant were measured to give the within-plant variation. The leaf and fruit characters were scored in millimeters using a Bausch and Lomb zoom lens dissecting microscope (0.7x-30x) and precision calipers. From pilot tests, the most important characters were selected for measurement. Table 3 lists the 18 morphological characters which were scored from each specimen. Transplants from each population were placed in two common gardens as well as in the greenhouse. The commongardens, B.Y.U. Botanical Shrub Nursery in Provo, Utah, and an experimental garden on the B.Y.U. Fa.rm in Spanish Fork, Utah, aided in removing most of the environmental differences which exist in natural populations and allowed for analysis of genetically controlled characters. The shrub nursery in Provo was irrigated weekly and weeded; whereas, the
Spanish Fork Garden was not maintained. Six specimens of each
6 7
TABLE2. Populations in the!• gardneri complex included in the studies of morphological variation
Species Number Location
!• ga.rdneri 2n=36 1 20 miles south Lovell, Wyoming 2 24 miles east Wamsutter, Wyoming 3 6 miles west Saco, Montana 4 50 miles north Casper, Wyoming 5 50 miles west Casper, Wyoming 6 6 miles south Sweetgrass, Montana !• gardneri 2n=18 7 1 mile east Red Desert, Wyoming !• faloata 2n=36 8 8 miles west Mu.dlake, Ida.ho !• falcata 2n=18 9 15 miles south Grouse Creek, Utah 10 27 miles west Austin, Nevada 11 15 miles south Wells, Nevada 12 1 mile west Rye Patch Res., Nevada !• tridentata 13 4 miles north Salina, Utah 14 1.5 miles west Ephraim, Utah 15 2 miles south Sigurd, Utah 16 1 mile north Grantsville, Utah 17 27 miles west Austin, Nevada !• corrugata 18 1 mile south Wellington, Utah 19 5 miles south Cisco, Utah 20 3 miles northeast Vernal, Utah !• welshii 21 5 miles south Cisco, Utah 22 8 miles east Green River, Utah !• cuneata 2n=36 23 5 miles south &l.ery, Utah 24 12 miles east Green River, Utah 25 5 miles north Price, Utah A. cuneata ssp. - introgressa 26 2 miles south Wellington, Utah ,A. ouneata 2n=18 27 3 miles south Bonanza, Utah 28 16 miles south Bonanza, Utah 8
TABLE3. Morphological characters which were statistically analyzed in selected populations of the!• p:ardneri complex
1. Plant height (measured from the ground to the termination of the flowering stalk) 2. Plant width (the north-south plant dimension) 3. Plant depth (the east-west plant dimension) 4. Leaf length (length of the blade but not including the petiole) 5. Leaf width (measured at the widest point) 6. Petiole length 7. Leaf length/width ratio a. Leaf angle {angle formed by the blade at the widest point) 9. Percent petiole 10. Fruit length (longitudinal dimension measured from the base of the lowermost bract to the tip of the terminal point) 11. Fruit width (width dimension which is parallel to the fusion cleft of the beak lips) 12. Fruit depth (width dimension which is perpendicular to the fusion cleft of the beak lips) 13. Pedicel length 14. Beak length (measured from the base of the cleft to the terminal point) 15. Beak width (measured at the base of the beak lips) 16. Number of terminal points (the number of shoulders over the terminal point) 17. Number of tubercules 18. Fruit length/width ratio 9 population were also maintained in the B.Y.U. Greenhouse for morpho- logical observations and comparisons. The morphological data were analyzed on a computer by multi- variate, cluster, a.nd discriminate a.na.J.yses. The multivariate analysis of variance program, a generalized analysis program developed by the Brigham Young University Statistics Department and capable of analyzing unbalanced (and balanced) univariate and multivariate analysis of variance problems as well as univariate and multivariate regression problems, aided in determining which characters were significantly different among plants, populations, and species. Tb.is analysis, coupled with both Duncan's and Newman Keul's Multiple Range Comparison Tests, not only aided in estab- lishing the distinct morphological characters but also assisted in grouping the populations into distinct entities or species. The results of this analysis were then checked by cluster analysis. The cluster analysis program, a program that creates a similarity index using sum(min)/sum(max) and arranges the phenogram by clustering the matrix via Sneath a.nd Sokal (1973), used all the population parameters and gave distinct groupings of the populations according to their morphological similarities. The discriminate analysis program performs a multiple discriminate analysis in a stepwise manner. At each step one variable is entered into the set of discriminating variables. The variable entered is selected by the first of the following equivalent criteria: (1) the variable with the largest F value, (2) the variable which when partialed on the previously entered variables has the highest multiple correla- tion with the groups, (;) the variable which gives the greatest 10 decrease in the ratio of within to total generalized variances.
The variable is deleted if the F value becomes too low. This analysis identifies those characters which could be used to best separate the species. The discriminate analysis program also computes canonical correlations and coefficients for canonical variables. It plots an optimal two-dimensional picture of the dispersion.
Results and Discussion Most species in the!• gardneri complex are highly poly- morphic and great variation is apparent between populations as well as within populations. Considerable variation was noted in the size and shape of the fruiting bracts, length and width of the leaves, and growth habits such as plant height, width, depth, and stature. Nevertheless, even in the presence of this vast variation, distinct combinations appear to be present even though many of the characters are not discretely disjunct. Tests on the leaf characters of male and female plants from three different populations were conducted to determine if the two sexes were morphologically different. The analysis of these populations (!. gardneri, 20 miles south of Lovell, Wyoming;!• ga.rdneri, 24 miles east of Wamsutter, Wyoming; and!• falcata, 8 miles west of Mud Lake, Idaho) included ten plants per population with five measurements per plant and five plants per sex. The results indicated that many of the plants in each population were signif- icantly different in many of their characters (see Tables 4 and 5). Those charaeters that showed a significant difference among plants 11
TABLE4. One-way analysis of variance of selected characteristics of male plants in three populations of Atriplex (all size measure- ments are in millimeters)
Population means Characters measured !• gardneri !• gardneri !• falcata Lovell, Wyo. Wamsutter, Wyo. Mud Lake, Ida.
Leaf length 30.68-IHE- 17.92iHI- 17.09-IHI- Leaf width 8.92-IHE- 6.12-IHI- 3.89-IHI- Petiole length 4.65-IHI- 2.95-IHI- 1.24* Leaf 1/w ratio 3.52* 2.94* 4.46* Leaf angle 56.60* 52.20 67.00* Percent petiole 13.01 14.01 6.87-IHI-
*Plant means are significantly different at **Plant means are significantly different at TABLE5. One-way analysis of variance of selected characteristics of female plants in three populations of Atriplex (all size measurements a.re in millimeters) Population means Characters measured !• gardneri !• ga.rdneri A. falcata Lovell, Wyo. Wamsutter, Wyo. MudLake, Ida. Leaf length 26.86* 16.31** 17.33 Leaf width 7.92 5.61** 3.44.* Petiole length 4.25 2.51* 1.26 Leaf 1/w ratio 3.45 3.00** 5.13 Leaf angle 56.80** 54.80** 71.20 Percent petiole 13.64 13.12 6.88 Fruit length 5.96** 4.78 3.64** Fruit width 3.16 2.75 2.22** Fruit depth 2.61** 1.75 1.56 Pedicel length 0.52 o.80 o.63** Beak length 1.44. 1.29 1.06 Beak width 0.94 0.91 0.49 # terminal points 3.32 2.72** 1.16 # tubercules 6.76 5.12** 6.80** Fruit 1/w ratio 1.93 1.79 1.68 *Plant means a.re significantly different at «=.05. HPlant means are significantly different at oc=.05. 13 in each of the populations varied from population to population. This was anticipated, however, since each population was thought to be a separate breeding group. The leaf characters of each population, which includes both sexes, showed some significant differences among the plants, but these did not always correlate with the differences that were expressed within each sex for each population (see Table 6). Thus, as can be seen in Table 4, each of the leaf characters of!• falcata male plants appears to be statistically different from all others; whereas, only one character in the female plants and three characters in the combined analysis expressed any detectable differences. The variation among the female plants increased the total variance of the analysis and, thus, diluted the contrast between plants. The above data suggests a real morphological difference between male and female plants of each area. Such bisexualism in morphological expressions is probably to be expected since female plants invest mu.ch of their photosynthetic energy in fruit development. However, a multivariate analysis of male plants against female plants in each population did not confirm this. As shown in Table 7, the male character means, although consistently larger than the female character means, are not statistically different from each other. Only one character, the leaf angle in !• falcata from near Mud Lake, Idaho, shows a significant difference between males and females. These results, then, indicate that female plants can serve as representative samples of an entire population. This reduces the number of samples required to be taken 14 TABLE 6. One-w~ analysis of variance of selected characteristics of three populations of Atriplex, including both sexes (all size measurements are in millimeters) Population means Characters measured !• gardneri !• gardneri !• falcata Lovell, Wyo. Wamsutter, Wyo. Mud Lake, Ida. Leaf length 28.77-'k-'k 17 .11-'k-'k 17.21-H Leaf width 8.42ff- 5.87-H 3.67-H Petiole length 4.45-IH(- 2.73-!Hf, 1.25 Leaf 1/w ratio 3.49-IHI- 2.97** 4.80 Leaf angle 56.70-lf-M- 53.50 69.10* Percent petiole 13.32 13.56 6.87 *Plant means are significantly different at °'=.05. **Plant means are significantly different at O< =.01. 15 TABLE7. Multivariate analysis for bisexualism in morphological expressions of three populations of Atriplex (all size measure- ments are in millimeters) Population means expressed by sex Characters !.• gardneri !.• gardneri !.• falcata measured Lovell, Wyo. Wamsutter, Wyo. Mud Lake, Ida. Female Male Female Male Female Male Leaf length 26.86 30.68 16.31 17.92 17.33 17.09 Leaf width 7.92 8.92 5.61 6.12 3.44 3.s9 Petiole length 4.25 4.65 2.51 2.95 1.26 1.24 Leaf 1/w ratio 3.45 3.52 3.00 2.94 5.13 4.46 Leaf angle 56.80 56.60 54.80 71.20 71.20 67.00* Percent petiole 13.64 13.01 13.12 14.01 6.88 6.87 *Plant means are significantly different at cx=.05. 16 from each population, because male plants need not be sampled. Even more important, the use of fruiting females increases the number of characters that can be evaluated statistically as representative samples. The sculpturing of the fruiting bracts is one of the most nearly constant and most used taxonomic criteria in the classifica- tion of the species of Atriplex, although the bracts vary greatly in the number and size of tubercules, not only between but also within plants. Smooth to strongly tuberculed fruits are found on single plants of some species, as also are both sessile and long- stalked ones. Nevertheless, much can usually be made of certain features of the fruiting bracts in separating most taxa in the Atriplex gardneri complex. Often the size alone is so different in even closely related species that this may be safely employed as a taxonomic criterion. Upon completion of a detailed morphological analysis of the fruits of a population of!.• welshii at Cisco, Utah, a multi- variate analysis program was conducted on the resultant data to see if, in fact, the between-plant variation was greater than the within-plant variation. Nine different characters were analyzed on ten plants with fifteen measurements per plant. From the results in Table 8, it can be concluded that all measured charac- ters showed between-plant variation to be statistically greater than within-plant variation. Therefore, most of the between-plant variation is probably a result of genetic differences. Since female plants are valid representatives of a population and since fruit characters can be used in characterizing 17 TABLE8. Multivariate analysis of fruit characteristics in ten plants of!• welshii; each plant is represented by n=15 (all size measurements are in millimeters) Plant number 1 2 3 4 5 Characters measured Plant means and variances c,-2 x o-2 x u2 -X o-2 x -X o-2 Fruit length 8.17 1.39 9.54 0.83 7.65 1.47 6.61 0.46 6.20 0.52 Fruit width 5.12 0.77 6.61 1.83 7.81 1.07 3.51 0.89 4.53 0.81 Fruit depth 5.17 2.67 5.05 8.12 6.70 1.28 2.56 1.00 3.68 2.12 Ped. Length 0.21 0.14 0.63 0.91 3.19 5.98 0.59 0.55 o.oo o.oo Beak length 1.85 0.64 2.82 0.28 2.54 0.16 1.810.361.40 0.37 Beak width 1.32 0.27 1.49 0.05 1.23 0.12 0.81o.081.01 0.03 Bea.kcleft fusion-IHI¼ 1.00 o.oo 1.00 o.oo 1.13 0.12 1.00 o.oo 1.00 o.oo # terminal points 3.00 o.oo 5.20 1.46 3.07 0.01 3.21 0.92 3.87 0.84 # tubercules 9.40 41.10 8.33 99.50 28.40 80.50 3.33 8.52 9.33 ao.50 *Plant means are significantly different at cx=.05. -lHf-Plantmeans are significantly different at OC=.01. -IHl¼Rated1-4 with 4 indicating complete fusion. 18 TABLE8. Continued Plant number 6 7 8 9 10 Grand mean Plant means and variances (1'2 (j2 cr2 q-2 x X X x a-2 x 6.82 o.67 5.99 0.83 9.29 1.11 6.56 0.76 6.73 0.40 7.36-H- 5.05 1. 71 4.86 1.04 6.35 0.51 5.13 0.65 5.39 1.21 5.44-H- 4.31 3.14 4.82 0.42 5.3a 1.03 4.11 2.08 5.15 0.10 4.69-H- o.oo o.oo o.oo o.oo 0.29 0.52 0.03 0.02 o.oo o.oo 0.49-H- 1.81 0.70 1.23 0.15 2.69 0.70 1.88 0.01 1.81 0.24 1.98-H- 1.21 0.91 0.51 0.03 1.31 0.01 0.91 0.03 1.12 0. 11 1.09ff 1.00 o.oo 1.00 o.oo 1.00 o.oo 1.00 o.oo 1.00 o.oo 1.01* 3.33 1.10 3.87 1.84 3.01 0.21 3.01 0.07 3.07 1.21 3.48H 9.47 48. 10 16.so 23.60 28.90 a9.80 14.40 135.00 19.50 125.0014-79,.. 19 Atriplex populations, fruiting plants from several populations in each species of the!• gardneri complex were carefully measured and analyzed. The characters used in this univariate and multivariate analysis are listed in Table 3; the means, staniard deviations, and coefficient of variation are recorded in Tables 9 through 17. A summary of all this data was recorded and grouped into species as well as sUlIIIIIBXizedat the species level. The placement of these populations into species was very systematic and this data will be presented later in this section. These univariate and multivariate analysis programs also provided statistical comparisons of the plants, populations, and species. As can be seen in Tables 9 through 17, most characters appear to be more variable between than within plants, which suggests that each plant in unique, and that the differences between plants are, at least partly, genetic. From the above results, it appears that most plants are genetically different in their respective populations and that each population mey be a genetically distinct ecotype. To further study the heritability of morphological differences, a multivariate analysis was made of!• gardneri, !• tridentata, and!• faloata. All of the characters listed in Table 3 were analyzed simultaneously for each population and then each population was compared to all other populations within each species. The results are expressed as chi square values. The chi square value for differences in populations of!• gardneri was 330.045 with 108 degrees of freedom. This chi sqU&Tevalue has an alpha value less than 0.0005. Such a low probability of "chance occurrence" strongly suggests that the 20 TABLE9. Means of measurements of habit, leaf, and fruit characters in!• gardneri populations (all size measurements are in millimeters) Populations Characters Lovell, Wyoming Wamsutter, Wyoming Saco, Montana x Plant height 376.o 7.86 20.9 161.0 7.40 46.o 159.0 4.79 30.1 Plant width 1231.0 38.17 31.0 464.0 16.35 35.2 440.0 11.29 25.6 Plant depth 1481.0 47.29 31.9 376.0 13.44 35.9 414.0 14.18 34.3 Leaf length 27.7* 6.40 23.1 17.3* 3.65 21.1 32.1*.4.27 13.3 Leaf width 7-9* 1.99 25.2 5.9* 1.33 22.5 11.8* 3.33 28.2 Petiole length 4.3* 1.34 31.2 2.8* 1.01 36.1 3.3* 0.96 29.1 Leaf 1/w ratio 3.4 0.82 24.1 3.0* 0.67 22.3 2.8* 0.50 17.9 Leaf angle 55.6* 11.30 20.3 54.4* 5.39 10.0 52.1* 6.13 11.8 Percent petiole 13.0 3.49 26.8 13.9 2.95 21.2 9.2 1.81 19.7 Fruit length 6.0* 1.57 26.2 4.9* 0.78 15.9 4.9* 1.05 21.4 Fruit width 3.4* 1.03 30.3 2.7 0.62 23.0 4.0* 1.56 39.0 Fruit depth 2.5* 0.95 38.0 1.9 0.55 28.9 2.7* 1.37 50.7 Pedioel length 1.0* 1.42142.0 o.8* o.63 78.8 1.2* 1.21100.8 Beak length 1.4 0.53 37.9 1.4* 0.59 42.1 1.2* 0.38 31.7 Beak width 2.2 7.28330.9 1.0* 0.57 57.0 o.6* 0.2a 46.7 # shoulders 5.9* 16.23275.1 2.5* 1.31 52.4 3.3* 1.21 36.7 # tuberoules 9.6 19.33a>1.4 6.3* 6.34100.6 11.2* 7.39 66.0 Fruit 1/w ratio 2.6 4.61177.3 1.8* 0.39 21.7 1.4* 0.44 31.4 *Significantly different at oc.:.05 (plant height, width, and depth not tested). 21 TABLE9. Continued Populations N. Casper, Wyo. Can.-USA Border w. Casper, Wyo. Red Desert, Wyo. x CV X <::r CV X er CV X q- CV 212.0 2.3s 11.2 166.0 3.73 22.5 211.0 6.41 23.4 291.0 6.27 21.5 1099.057.76 52.6 344.0 8.97 26.1449.013.71 30.5 584.0 12.92 22.1 983.0 63.40 64.5 330.0 4.53 13.7 414.0 7.82 18.9 629.0 14.21 22.6 26.8* 3.45 12.9 31.9* 6.52 20.4 42.7* 5.92 13.9 32.0* 6.53 20.4 8.1* 1.56 19.3 9.2* 2.05 22.3 13.4* 2.69 20.1 7.1* 1.38 19.4 3.1* 1.28 34.6 2.1* 1.08 51.4 7.0* 2.55 36.4 5.2* 1.66 31.9 3.4* 0.59 17.4 3.6* 0.1a 21.7 3.3* 0.47 14.2 4.5* o.88 19.6 57.2* 4.69 8.2 59.5* 5.58 9.4 65.3* 3.76 5.8 71.9* 3.53 4.9 12.0* 3.26 27.2 5.9* 2.22 37.6 13.9* 4.21 30.3 13.8* 2.99 21.7 5. 1 * O. 82 16. 1 3.8* o.s2 21.6 5.3 0.1a 14.7 4.8* 0.60 12.5 3-3* 1.14 34.5 2.4* o.81 33.8 3.1* 0.59 19.0 2.6* 0.45 11.3 1.6* o.69 43.1 1.4 0.43 30.7 1.9 0.48 25.3 1.5 0.41 27.3 o.5* 0.40 80.o 0.8* 0.71 88.8 0.8* 0.39 48.8 0.9 0.36 40.0 1.0* 0.31 31.0 1.0* 0.49 49.0 1.1 0.39 35.5 1.0* 0.36 36.0 0.1 0.27 38.6 0.7 0.35 50.0 0.5* 0.22 44.0 ·0.4* 0.22 55.0 3.6* 1.63 45.3 2.6 1.07 41.2 2.8* 1.63 58.2 3.4* 1.44 42.4 3.3* 3.39 102.7 7.2* 4.30 59.7 3.0 2.13 71.0 3.3* 3.19 96.7 1.7* 0.41 24.1 1.6 0.30 18.8 1.8* 0.35 19.4 1.9* 0.32 16.8 22 TABLE 10. Summal.'y of habit, leaf, and fruit character means in!• gardneri populations (plant height, width, and depth in centi- meters, all other size measurements a.re in millimeters) Populations Characters Grand totals X CV Plant height 23.5 9.62 40.9 Plant width 65.9 43.21 65.6 Plant depth 66.1 50.26 76.0 Leaf length 30.1* 8.87 29.5 Leaf width 9.1* 3.26 35.a Petiole length 4.0* 2.13 53.3 Leaf 1/w ratio 3.4* 0.86 25.3 Leaf angle 59.4* a.92 15.0 Percent petiole 11.7* 4.16 35.6 Fruit length 5.0* 1.13 22.6 Fruit width 3.1* 1.07 34.5 Fruit depth 1.9* 0.90 47.4. Fruit pedicel length 0.9 0.84 93.3 Fruit beak length 1.1* 0.48 43.6 Fruit beak width 0.9 2.80 311.1 # fruit shoulders 3.4 6.29 185.0 # fruit tubercules 6.3* a.99 142.7 Fruit 1/w ratio 1.8 1.79 99.4 . ~ignificantly different at oc=.05 (plant height, width, and depth not tested). 23 TABLE11. Means of measurements of habit, leaf, and fruit charac- ters in!• tri6:entata populations {data ta.ken from 7 plants per population and measurements per plant; all size measurements·in mm) Populations Characters Ephraim, Utah Salina, Utah Sigurd, Utah x CV X CV X 0- CV Plant height 366.0 5.00 13.7 321.0 3.32 10.3 640.0 6.30 9.8 Plant width 533.0 13.56 25.4 467.0 12.85 27.5 a36.o 1a.24 21.a Plant depth 604.0 22.74 37.6 443.0 a.67 19.6 867.0 15.92 18.4 Leaf length 27.3* 6.58 24.1 22.7* 3.95 17.4 28.8 4.79 16.6 Leaf width 5.5* 1.56 28.4 3.5* 0.79 22.6 4.9* 0.74 15.1 Petiole length 1.6* 0.10 43.a 1.4 0.39 27.9 1.1 0.37 33.6 Leaf 1/w ratio 5.1* 0.92 18.0 6.5 1.40 21.5 5.9* 1.18 20.0 Leaf angle 71.6* 2.91 4.1 74.0 2.03 2.7 71.9* 3.45 4.8 Percent petiole 5.7* 1.90 33.3 6.0* 1.59 26.5 3.7* 1.27 34.3 Fruit length 5.7* o.81 14.2 4.6* o.a1 17.6 6.2* 1.00 16.1 Fruit width 4.3 0.63 14.7 3.7* o.ao 21.6 4.2* 0.94 22.4 Fruit depth 1.9* 0.67 35.3 1.4* 0.40 28.6 1.9* 0.76 40.0 Pedicel length 0.2* 0.27 1.4 0.1* 0.31 310.0 o.2* 0.53 2.6 Beak length 1.5 0.39 26.0 1.3* 0.49 37.7 1.9* 0.51 26.8 :Beak width 1.0* 0.36 36.0 o.6* 0.25 41.7 1.3* 0.44 33.a # shoulders 4.9* 1.45 29.6 5.5* 1.77 32.2 5.6* 1.48 26.4 # tubercules 3•2* 3.77 117.8 2.0* 2.78 139.0 2.7* 2.67 98.9 Fruit 1/w ratio 1.4* 0.19 13.6 1.3* 0.22 16.9 1.5* 0.37 24.7 ifSignificantly different at TABLE11 • Continued Populations Grantsville, Utah Austin, Nevada Grand totals X tr av X O' av X CV 329.0 8.55 25.9 210.0 4.40 20.9 373.0 15.46 41.4 504.0 17.90 35.5 451.0 21.06 46.7 558.0 21.99 39.4 417.0 13.50 32.4 410.0 14.19 34.6 548.0 23.38 42.7 23.9* 4.54 19.0 15.1* 3.29 21.8 23.6* 6.72 28.5 4.1* 0.82 20.0 3. 7JJ.·0.59 15.9 4.3* 1.20 27.9 1.1 0.36 32.7 0.8* 0.33 41.3 1.2* 0.52 43.3 5.9* 1.19 20.2 4.2* 0.88 20.9 5-5* 1.34 24.4 71.3* 3. 71 5.2 65.1* 2.84 4.4 70.8* 4.23 6.o 4.3 1.43 33.3 5.2* 1.63 31.3 5.0* 1. 78 35.6 4.3* 0.77 17.9 4.6-iE·0.52 11.3 · 5.1* 1.08 21.2- 3.0* 0.61 20.3 3.3* 0.67 20.3 3-7* 0.89 24.1 1.6* 0.53 33.1 2.3* 0.81 35.2 1.8* 0.12 40.0 0.1 0.20 2.0 0.4* 0.59147.5 0.2* 0.42 200.1 1.1* 0.49 44.5 1.4 0.46 32.9 1.4* 0.55 39.3 o.6* 0.21 35.0 0.9 6.42 46.7 0.9* 0.44 48.9 3.7* 1.21 32. 7 3.5* 1.09 31.1 4.6* 1.67 36.3 4.0* 3.21 80.3 7.9* 5.57 70.5 4.0* 4.21 106.8 1.5* 0.24 16.0 1.5 0.33 22.0 1.4* 0.29 20.7 25 TABLE12. Means of measurements of habit, leaf, and fruit charac- ters in!• corrugata populations (all size measurements are in mm)· Populations Characters Wellington, Utah Cisco, Utah X CV X CV Plant height 58.0 1.80 31.0 128.0 10.31 80.5 Plant width 459.0 17.30 37.7 445.0 18.30 41.1 Plant depth 419.0 19.35 46.2 536.0 25.68 47.9 Leaf length 7.5* 1.75 23.3 8.3* 1.97 23.7 Leaf width 2.3* 0.35 15.2 2.3 0.52 22.6 Petiole length 0.3* 0.14 46.7 o.6* 0.27 45.0 Leaf 1/w ratio 3.3* 0.79 23.9 3.5 0.84 24.0 Leaf angle 62.0* 2.49 4.0 63.4 11.49 18.1 Percent petiole 3.5* 2.10 60.0 6.2* 2.70 43.5 Fruit length 3.5 0.36 10.3 3.6 0.77 21.4 Fruit width 2.1* 0.28 13.3 2.1 0.51 24.3 Fruit depth 2.0 0.37 18.5 1.1* 0.44 40.0 Pedicel length o.6* 0.21 35.0 0.4* 0.36 90.0 Beak length 1.3* 0.24 18.5 0.9* 0.27 30.0 Beak width 1.9* 0.21 14.2 2.5 1.68 67.2 # shoulders 1.0* o.oo o.o 2.3* 7.43 3.2 # tubercules 11.3* 4.53 40.1 7.6 9.44 124.2 Fruit 1/w ratio 1. 7* 0.25 14.7 1.9 1.36 71.6 *Significantly different at OC=.05(plant height, width, and depth not tested). 26 TABLE12. Continued Vernal, Utah Grand totals X CV X CV 74.0 2.20 29.7 87.0 6.83 78.5 273.0 5.25 19.2 392.0 16.98 43.3 281.0 6.17 22.0 412.0 21.45 52.1 7.4* 2.00 27.0 1.1 1.93 25.1 1.9* 0.46 24.2 2.2 0.48 21.8 o. 3* 0.34 113.3 0.4* 0.29 72.5 3.9* 0.72 18.5 3.6 0.82 22.8 69.6* 3.91 5.6 65.0* 7.81 12.0 4.1* 4.07 99.3 4.6 3.26 70.9 4.5* 0.52 11.6 3.9* 0.72 18.5 3.3* 0.42 12.7 2.5* 0.69 27.6 2.8* 0.58 20.7 2.0* 0.84 42.0 o.o* 0.41 51• .5 o.6* 0.38 63.3 1.7 0.37 21.8 1.3* 0.44 33.8 3.0* 0.45 15.0 2.4* 1 .11 46.3 1.0* o.oo o.o 1.4 4.29 306.4 12.6* 5.07 40.2 10.5 6.98 66.5 1.4* 0.24 11.1 1.7 0.84 49.4 27 T.AJ3LE13. Means of measurements of habit, leaf, and fruit charac- ters in A. f'a.lcata populations (data taken from 7 plants per population and 5 measurements per plant; all size measurements in mm) Populations Characters Mud Lake, Ida.ho Grouse Creek, Ut. Austin, Nevada X 0- CV X (T CV Plant height 244.0 5.06 20.7 169.0 4.45 26.3 211.0 6.5a 31.2 Plant width 326.0 4.24 13.0 309.0 5.1a 16.a 303.0 10.52 34.7 Plant depth 313.0 3.35 10.7 274.0 5.35 19.5 346.0 16.47 47.6 Leaf length 16.8* 2.10 12.5 22.7 4.50 19.8 21.5* 3.67 17.1 Leaf width 3.5* 0.52 14.9 2.8* 0.5a 20.1 4.5* 0.94 20.9 Petiole length 1.2 0.07 5.a 1.0* 0.22 22.0 1.3* 0.19 14.6 Leaf 1/w ratio 4.6 0.46 10.0 9.3* 3.56 38.3 4.8* 0.46 9.4 Leaf angle 70.0* 2.31 3.3 76.0* 2.31 3.0 70.0* 2.43 3.5 Percent petiole 6.5 0.81 12.5 4.5* 0.95 21.1 5.7* 0.83 14.6 Fruit length 3.6* 0.48 13.3 4.0 0.29 7.3 3.7* 0.29 7.4 Fruit width 2.1* 0.35 16.7 2.2 0.16 7.3 2.2* 0.34 15.5 Fruit depth 1.5 0.24 16.0 1.5 0.08 5.3 1.1* 0.34 20.0 Pedicel length 0.1* 0.10 100.0 0.3 0.22 73.3 0.5 0.14 28.0 Beak length 1.0* 0.19 19.0 1.4 0.20 14.? 1.5* 0.23 15.3 Beak width o.5* 0.13 26.0 o.8 0.14 17.5 1.0 0.10 10.0 # shoulders 1.1* 0.30 27.3 1.0* o.oo o.o 1.0* o.oo o.o # tubercules 5.5* 5.40 98.2 3.1* 3.25100.6 9.3* 4.50 4a.4 Fruit 1/w ratio 1.7* 0.21 12.4 1.8 0.15 e.3 1.8 0.22 12.2 *Significantly different at oc.•• 05 (plant height, width, and depth not tested). 28 TABLE13. Continued Wells, Nevada Rye Patch Res., Nev. Grand totals x rr CV X CV X CV 236.0 5.35 22.7 135.0 4.74 41.2 199.0 6.18 31.1 213.0 6.32 29.7 138.0 3.90 28.3 256.0 9.37 36.6 211:.0 3.44 16.3 146.0 3.78 25.9 258.0 10.47 40.6 26.8* 5.10 19.0 42.2* 6.58 15.6 26.0* 10.00 38.5 3.8* 0.78 20.5 6.8* 1.81 26.6 4.3* 1.79 41.6 1.3* 0.34 26.2 1.6* 0.55 34.4 1.3* 0.44 33.8 7.4* 1.33 18.0 6.5* 1.55 23.8 6.6* 2.56 38.8 78.3* 2.98 3.8 74.4* 2.84 3.8 73.8* 4.51 6.1 4.5* 1.03 22.9 3.7* 1.03 27.8 5.1* 1.79 35.1 3.9* 0.41 10.5 4.8* 0.67 13.9 4.1* 0.74 18.0 2.3* 0.57 24.7 2.1* 0.26 12.4 2.2 0.43 19.5 1.6* 0.29 18.1 1.4* 0.28 20.0 1.5 0.39 26.0 o.6 0.22 36.7 2.0* 0.96 48.0 0.8* 0.91 113.s 1.7 0.20 11.8 1.6* 0.53 33.1 1.4* 0.48 34.3 0.8* 0.21 33.8 0.5* 0.14 28.0 0.1* 0.31 44.3 1.0* o.oo o.o 1.0* o.oo o.o 1.0 0.21 21.0 6.4 1.88 29.4 10.0* 3.71 37.1 6.9* 5.75 83.3 1.8* 0.24 13.3 2 .4 0.31 12.9 1.9* 0.47 24.7 29 TABLE14. Means of measurements of habit, leaf, and fruit chaxac- ters in A•welshii populations (all size measurements in mm) Characters Cisco, Utah -X CV Plant height 176.0 3.28 18.6 Plant width 430.0 11.78 27.4 Plant depth 391.0 8.41 21.5 Leaf length 19.3* 6.81 35.3 Leaf width 4.5* 0.59 13.1 Petiole length 2.6* 0.42 16.2 Leaf 1/w ratio 4.4* 0.64 14.5 Leaf angle 66.4* 2.51 3.a Percent petiole 12.1* 2.18 18.0 Fruit length 1.a* 1.75 22.4 Fruit width 5.6* 1.46 26.1 Fruit depth 4.8* 1.31 27.3 Fruit pedicel length 0.2 0.22 110.0 Fruit beak length 2.0* 0.1a 39.0 Fruit beak width 1.1* 0.41 37.3 # fruit shoulders 3.7* o.a1 23.5 # fruit tubercules 14.8* a.49 57.4 Fruit 1/w ratio 1.5* 0.25 16.7 ifSignificantly different at 0( •• 05 (Plant height, width, and depth not tested). 30 TABLE14. Continued Populations Green River, Utah Grand totals -X CV X CV 250.0 4.50 18.0 213.0 5.38 25.3 453.0 13.24 29.2 441.0 13.12 29.s 410.0 9.32 22.7 401.0 s.70 20.1 29.9* 5.72 19.1 24-.6* 7.37 30.0 3.5* 0.47 13.4 4.0* 0.83 20.8 1.3* 0.34 26.2 2.0* 0.82 41.0 8.5~-.. 1.05 12.4 6.4* 2.39 37.3 77.7* 2.12 2.1 72.1* 6.51 9.0 4.3* 1.78 41.4 8.2* 4.42 53.9 6.0* 1.23 20.5 6.9* 1.77 25.7 4.2 0.46 11.0 4-9* 1. 51 50.8 2.8 0.15 5.4 3.8* 1. 79 47.1 0.8* 0.42 52.5 0.5* 0.58 116.0 2.2* 0.46 20.9 2.1 0.79 37.6 0.8* 0.37 46.3 0.9 0.45 50.0 3.3 0.40 12.1 3.5 1.11 31.7 20.7 3.38 16.3 17.8 9.68 54.4 1.4* 0.20 14.3 1.5 0.32 21.3 31 TABLE15. Means of measurements of ha.bit, leaf, and fruit charac- ters in the!• cuneata ssp. introgressa population (all size measurements a.re in millimeters) Population Characters 1 mile south Wellington, Utah X CV Plant height 162.0* 5.08 31.4 Plant width 299.0* 8.83 29.5 Plant depth 321.0 12.65 39.4 Leaf length 21.4* 2.42 11.3 Leaf width 4.9* 1.02 20.8 Petiole length 2.2 0.99 45.0 Leaf 1/w ratio 4.6* 1.10 23.9 Leaf angle 65.4* 4.09 6.3 Percent petiole 9.1* 3.88 42.6 Fruit length 7.6* 1.18 15.5 Fruit width 5.0* 1.39 27.8 Fruit depth 4.6* 1.33 28.9 Fruit pedicel length 2.5* 1.13 45.2 Fruit beak length 3.1* o.e8 28.4 Fruit beak width 1.8* 0.19 43.9 # fruit shoulders 2.0* 1.45 72.5 # fruit tubercules 21.1* 8.04 38.1 Fruit 1/w ratio 1.6* 0.36 22.5 -MSignificantly different at OC=.05. 32 T.A:BLE16. Means of measurements of habit, leaf, and fruit charac- ters in diploid A. cuneata populations (2n=18); all size measure- ments are in millimeters Characters 3 miles south Bonanza, Utah x CV Plant height 366.0 5.79 15.8 Plant width 580.0 16. 72 28.8 Plant depth 567.0 26.37 46.5 Leaf length 39.0* 4.68 12.0 Leaf width 23.7* 4.37 18.4 Petiole length 8.4* 1.85 22.0 Leaf 1/w ratio 1.7* 0.26 15.3 Leaf angle 37.7* 6.78 18.0 Percent petiole 17.8* 3.41 19.2 Fruit length 5.2* 0.75 14.4 Fruit width 5.6* 1.29 23.0 Fruit depth 3.6* 0.78 21.7 Fruit pedicel length 2.5* 0.91 36.4 Fruit beak length 1.2 0.36 30.0 Fruit beak width 0.2 0.06 30.0 # fruit shoulders 1.0 o.oo o.o # fruit tubercules 15.7* 6.99 44.5 Fruit 1/w ratio 1.0 0.22 22.0 *Significantly different at «=.05. 33 TABLE16. Continued Populations 16 miles south Bonanza, Utah Grand totals x 317.o 2.28 7.2 331.0 4.60 13.9 617.0 17. 70 28.7 599.0 17.19 28.7 597.0 15.09 25.3 582.0 21.38 36.7 30.9* 4.99 16.1 35.0* 6.30 18.0 15.2* 2.90 19.1 19.5* 5.65 29.0 1-9* 2.30 29.1 8.2 2.09 25.5 1.8* 0.35 19.4 1.7 0.31 18.2 49.1* 7.79 15.9 43-4* 9.22 21.2 20.2* 3. 71 18.4 19.0 3.73 19.6 5.1* 1.10 21.6 5.1 0.94 18.4 5.0* 1.40 28.0 5.3 1.38 26.0 2.9* 0.82 28.3 3.2 0.87 27.2 2.2* 1.37 62.3 2.4 1.16 48.3 1.1* 0.49 44.5 1.1 0.43 39.1 0.3 0.20 66.7 0.3* 0.16 53.3 1.1 0.37 33.6 1.0 0.27 21.0 13. 7* 4.00 29.2 14. 7 5.75 39.1 1.1* 0.29 26.4 1.0 0.27 27.0 34 TABLE17. Means of measurements of habit, leaf, and fruit charac- ters in tetraploid !• cimeata populations (2n=36); all size measurements are in millimeters Populations Characters .Emery, Utah Green River, Utah -X er CV X CV Plant height 179.0 4.31 24.1 252.0 4.38 17.4 Plant width 951.0 26.42 27.8 581.0 12.07 20.8 Plant depth 1006.0 30.37 30.2 640.0 18.17 28.4 Leaf length 14.5* 2.96 20.4 24.5* 3.81 15.6 Leaf width 8.5* 1.32 15.5 12.3* 2.27 18.5 Petiole length 2.4* 0.64 26.7 4.2* 0.99 23.6 Leaf 1/w ratio 1.7* 0.23 13.5 2.0* 0.37 18.5 Leaf angle 38.7* 5.98 15.5 41.3* 6.46 15.6 Percent petiole 14.2 2.64 18.6 14.7* 2.53 17.2 Fruit length 4.3* 0.70 16.3 6.3* 1.11 17.6 Fruit width 3.5* 0.89 25.4 4.6 1.10 23.9 Fruit depth 2.9* 1.01 34.8 3.8 1.09 2e.7 Pedicel length 0.9* 0.57 63.3 2.5* 1.50 60.0 Beak length 1.0* 0.33 33.0 1.7* 0.55 32.4 Beak width o.6 0.29 48.3 1.1* o.64 58.2 # shoulders 1.6 0.94 58.8 2.4 1.04 43.3 # tubercules 16.7* a.22 49.2 17.7* 6.51 36.8 Fruit 1/w ratio 1.3 0.28 21.5 1.4 0.38 27.1 il-Significantly different at 0<=.05. 35 TABLE17. Continued Populations Price, Utah Grand 'l'otals X q-· CV X (j CV 204.0 4.88 23.9 212.0 5.43 25.6 971.0 32.55 33.5 835.0 30.77 36.9 969.0 26.55 27.4 871.0 30.21 34.7 18.3* 4.01 21.9 19.1* 5.47 28.6 9.9* 2.33 23.5 10.2* 2.55 25.0 2.9* 1.08 37.2 3.2* 1.20 37.5 1.9* 0.43 22.6 1.9 0.37 19.5 43.1* G.75 20.3 41.0 7.33 17.9 13.5* 3.34 24.7 14.1 2.88 20.4 4.8* 0.16 15.8 5.1* 1.21 23.7 3.8 o. 73 19.2 4.0* 1.02 25.5 3.3* 0.91 27.6 3.3 1.09 33.0 1.0 0.61 61.0 1.5* 1.22 81.3 1.1* 0.40 36.4 1.3* 0.52 40.0 ' o.6 0.26 43.3 0.1* 0.50 71.4 2.0* 1.12 56.0 2.0 1.08 54.0 19.0* 4.89 25.7 17.a 6.68 37.5 1.3 0.21 16.2 1.3 0.30 23.1 36 differences between populations a.re not random and, thus, further supports the interpretation that each population measured is a genetically distinct ecotype. The results of a one-way analysis of variance for each character to determine which characters were most responsible for the high chi square a.re asterisked in Table 9. As can be seen, all characters except pedioel length, fruit beak width, number of fruit shoulders, and fruit 1/w ratio show signif- icant variation. The chi square value for differences between ';t populations of!• tridentata was 309.~ with 128 degrees of freedom and for!• falcata was 192.00 with 72 degrees of freedom (both have alpha values less than 0.0005). All characters (except plant depth) for!• tridentata (Table 11) and fruit width, fruit depth, and the number of fruit shoulders for!• falcata (Table 13) were signif- icantly different, and were thus contributing to the high chi square ·values. A summary of each species table (Tables 9 through 17) is given in Table 18 which allows for a comparison of each character in all species. This multivariate analysis of all species yielded a chi square of 309.797 with 126 degrees of freedom which supports the hypothesis that the species a.re genetically different. As also appears in Table 18, each character, with the exception of plant depth, shows at least one population to be different from all the other populations. Duncan's New Multiple Range Comparison Test was used to detect which species a.re different in each of the characters which show significant statistical differences in Table 18. For instance, plant height (Table 19) is one character that can be used to 37 T.A:BLE18. Summary of means of measurements of habit, leaf and fruit characters in each species in the!• gardneri complex (summary of Tables 9 through 17); all size measurements are in millimeters Populations Characters !• ga.;rdneri !• 9eri A. cuneata 2n=18 2n=3 - 2n=36 x er CV I () CV x (J CV Plant height 291.0 6.; 21.5 225.0 9.8 43.5 212.0 5.2 25.5 Plant width 584.0 12.9 22.1 671.0 46.3 69.0 835.0 30.8 36 •.9 Plant depth 629.0 14.2 22.6 666.o 54.0 81.1 871.o 30.2 34.7 Leaf length 32.0 6.5 20.4 29.8 9.2 30.8 19.1 5.5 28.8 Leaf width 7 .1 1.3 18.6 9.4 3.4 35.9 10.2 2.6 25.5 Petiole length 5.2 1.6 31.9 3.9 2.2 55.1 3.2 1.2 37.5 Leaf 1/w ratio 4.6 0.9 19.1 3.3 0.7 21.2 1.9 0.4 21.1 Leaf angle 71.9 3.5 4.9 57.3 7.8 13.6 41.0 7.3 17.8 Percent petiole 13.8 3.0 21.7 11.3 4.2 37.3 14.1 2.9 20.6 Fruit length 4.8 o.6 12.5 5.0 1.2 24.0 5.1 1.2 23.5 Fruit width 2.6 0.4 16.9 3.1 1.1 36.1 4.0 1.0 25.0 Fruit depth 1.5 0.4 27.3 2.0 0.9 47.0 3.3 1.1 33.3 Pedicel length 0.9 0.4 40.0 o.8 0.9 112.5 1.5 1.2 80.o Beak length 0.9 0.4 40.0 1.2 0.5 40.8 1.3 0.5 38.5 Beak width 0.4 0.2 55.0 1.0 3.0 301.0 0.1 0.5 71.4 # shoulders 3.4 1.4 42.4 3.4 6.8 199.0 2.0 1.1 55.0 # tubercules 3.2 3.2 99.7 6.8 9.5 140.1 17.8 6.7 37.6 Fruit 1/w ratio 1.9 0.3 16.8 1.8 1.9 107.2 1.3 0.3 23.1 38 TABLE 18. Continued ., Populations !• cuneata 2n=18 !• corrugata !• tridentata !• falcata X (T CV -X (T CV X (f CV X Cf CV 331.0 4.6 13.9 87.0 6.8 78.2 373.0 15.5 41.6 199.0 6.2 31.2 5·99.0 1,7.2 28. 7 392.0 17.o 43.4 558.0 22.0 39.4 258.0 9.4 36.4 582.0 21.4 36.3 412.0 21.5 52.2 548.0 23.4 42. 7 258.0 10.5 40.7 18.0 23.6 28.4 26.0 10.0 38.5 35.0 6.3 7.7 1.9 24.7• 6.7 19.5 5.6 28.7 2.2 0.5 22.7 4.3 1.2 27.9 4.3 1.8 41.9 8.2 2.1 25.6 0.4 0.3 75.0 1.2 0.5 41.7 1.3 0.4 30.s 1.7 0.3 17.6 3.6 o.s 22.2 5.5 1.3 23.6 6.6 2.6 39.4 4-3.4 9.2 21.2 65.0 1.s 12.0 70.s 4.2 5.9 73.8 4.5 6.1 19.0 3.7 19.5 4.6 3.3 71. 7 5.0 1.8 36.0 5.1 1.8 35.3 5.1 0.9 17.6 3.9 0.1 17.9 5.1 1.1 21.6 4.1 0.1 11.1 5.3 1.4 26.4 2.5 0.1 28.0 3.7 0.9 24.3 2.2 0.4 18.2 3.2 0.9 28.1 2.0 o.a 40.0 1.8 0.1 38.9 1.5 0.4 26.7 2.4 1.2 50.0 o.6 0.4 66.7 0.2 0.4 200.0 o.8 0.9 112.5 1.1 0.4 36.4 1.3 0.4 30.8 1.4 0.5 35.7 1 .4 0.5 35.7 0.3 0.2 66.7 2.4 1.1 45.8 0.9 0.4 44.4 · o. 7 0.3 42.9 1.0 0.3 30.0 1..4 4.3 307.1 4.6 1.7 37.0 1.0 0.2 20.0 14. 7 5.7 38.8 10.5 1.0 66.7 4.0 4.3 107.5 6.9 5.7 82.6 1.0 0.3 30.0 1.7 0.8 47.1 1.4 0.3 21.4 1.9 0.5 26.3 39 TABLE 1S. Continued Populations Characters !• welshii -A. -cun. ssp. intro. F ratio X rr CV X (f CV Plant height 213.0 5.4 25.4 162.0 5.1 31.5 3-44* Plant width 441.0 13.1 29.7 289.0 8.8 30.4 2.60* Plant depth 401.0 8.7 21.7 321.0 12.7 39.6 2.00 Leaf length 24.6 7.4 30.1 21.4 2.4 11.2 4.05* Leaf width 4.0 0.8 20.0 4.9 1.0 20.4 15.53* Petiole length 2.0 0.8 40.0 2.2 1.0 45.5 16.25* Leaf 1/w ratio 6.4 2.4 37.5 4.6 1 .1 23.9 8.36* Leaf angle 72.1 6.5 9.0 65.4 4.1 6.3 17.31* Percent petiole 8.2 4.4 53.7 9.1 3.9 42.9 15.06* Fruit length 6.9 1.8 26.1 7.6 1.2 15.8 6.05* Fruit width 4.9 1.5 30.6 5.0 1 .4 28.0 13.16* Fruit depth 3.e 1.8 47.4 4.6 1 .3 28.3 9.56* Pedicel length 0.5 o.6 120.0 2.5 1 .1 44.0 7-59* Beak length 2 .1 0.8 38.1 3.1 0.9 29.0 8.40* Beak width 0.9 0.4 44.4 1.8 o.e 44.4 6.51* # shoulders 3.5 1 .1 31.4 2.3 1.5 65.2 14. 72* # tubercules 17.8 9.7 54.5 21.1 8.-0 37.9 14.76* Fruit 1/w ratio 1.5 0.3 20.0 1.6 0.4 25.0 3.84* --Significantly different at ot •• 05. 40 TABLE19. Duncan's New Multiple Range Test on all species in the Atriplex ga;dneri complex. Significant characters in Table 16 _ were tested. Species are numbered as follows: (1) !• gardneri, (2) !• falcata, (3) A. tridentata, (4) !• cop;ugata, (5) A. w~lshii, (6) !• cuneata (2n=36), (7) !• cuneata ssp. introgressa, "[a)!• cuneata {2n=18). Plant height Species# 4 7 2 6 5 1 8 3 -lHE- * * * * * 8 * 1 * 5 6 2 7 Plant width Species If 2 7 4 5 3 8 1 6 -lHE- * * 1 * 8 3 5 4 7 41 TABLE 19. Continued Leaf length Species# 4 6 7 3 5 2 1 8 ** * 1 ** 2 *i<- 5 * 3 ** 7 6 Leaf width Species# 4 5 2 3 7 1 6 -lH(- 8 ** ** ** ** 6 ** * ** ** 1 ·X· ** ** 7 3 2 5 42 TABLE 19. Continued Petiole length Species# 4 3 2 5 7 6 1 8 ** ** ** -lE-lE- ** 1 ** ** ** * 6 ** * * 1 5 2 3 Leaf 1/w ratio Species # 8 6 1 4 1 3 5 2 ** ** ** ** 5 ** ** ** * 3 ** ** * * 7 4 1 6 43 TABLE 19. Continued Leaf angle Species # 6 8 1 4 7 3 5 2 ** ** ** 5 ** -x-l<· * 3 ** -;H(· 7 ** ** 4 ** ** 1 -lHE- ** 8 Percent petiole Species # 4 3 2 5 7 1 6 8 ** ** ** ** ** * 6 ** ** ** * 1 ** ** 7 5 2 3 44 TABLE 1,. Continued Fruit length Species # 4 2 1 3 6 8 5 7 ** ff ** ff * * 5 ff ff ** * * * 8 * -IC· 6 * * 3 * * 1 * * 2 Fruit width Species# 2 4 1 3 6 5 7 -)(--if, 8 ** ff ** * 7 ff ** ff * 5 ** ** ·if* * 6 ff ff * 3 ** * 1 * 4 45 TABLE 19. Continued Fruit depth Species# 2 3 1 4 8 6 5 7 ff ff ff ** 5 ** ** ** ** 6 ff ** ** ff· 8 ** ** ** * 4 1 3 Pedicel length Species # 3 5 4 2 1 6 8 7 ** ** ** ** ff * 8 ** ** ** ** ff * 6 ff * * 1 * 2 4 5 46 TABLE 19. Continued Beak length Species # 8 1 4 6 2 3 5 7 ** -lE--l,- ii-It- iE-l!- 5 ~<-* *·K -IH(· ** * * 3 2 6 4 1 Beak width Species# 8 2 6 3 1 5 7 4 ** ** ** ** 7 * 5 1 3 6 2 47 TABLE 19. Continued Number of shoulders Species# 2 8 4 6 7 1 5 3 ff ff ** ff * * 5 ** * * * 1 ** ** ** * 7 6 4 8 Number of tubercules Species # 3 1 2 4 8 5 6 7 ff ff ** ** 6 ff ff ** ** 5 ** ** ** * 8 ** ** ** 4 ** * 2 1 48 TABLE 19. Continued Fruit 1/w ratio Species# 8 6 3 5 7 4 1 2 ·X·* -¥.· * 1 *"l<· * * 4 * 7 5 3 6 *Probability less than .01 -ff-Probability less than .05 49 distinguish!• tridentata from all other Atriplex in this study except!• cuneata (2n=18); !• corrugata can also be separated from !• tridentata, !• cuneata (2n=18), and!• gardneri. Likewise, on the basis of plant width,!• cuneata (2n=36) can be distinguished from!• falcata, !• cuneata ssp. introgressa, and!• cor;,;ugata and !• falcata from!• gardneri. Thus, if one were to compile all of the information from Table 19 into one unit, then species parameters could be extrapolated. This, however, likely would be a rather cumbersome program. A simpler program is available which performs a discriminating analysis on the total data and the results would probably be similar to the compiled data in Table 19 (this discrim- inant analysis program is discussed below). Nevertheless, the Duncan Multiple Range Comparison Test Program is of other value in that it indicates which species a.re statistically different from each other for each character analyzed. Before a complete discussion can take place on the establish- ment of population parameters, several species need to be defined as to which populations they include. From extensive field: work, it appears that most populations of!• falcata, !• tridentata, !• corrugata, and!• cuneata are relatively distinct both morpho- logically and ecologically. The diploid populations of A. welshii and!• cuneata ssp. introgressa, however, are more difficult to distinguish (see Fig. 1). The morphological and ecological similarities of these two species are quite noteworthy. Both grow in the Green River drainage area and occupy comparable habitat types on ma.ncos shale wastelands. They also appear to express similar growth habits and fruit types. They do differ 1omewhat VI 0 Fig. 1. Bar. graphs of the averages of four fruit characters in diploid populations of Atriplex: (1) !• falcata, Mud Lake, Ida.ho; (2) !• Falcata, Grouse Creek, Utah; (3) !• falcata, Austin, Nevada; (4) !• falcata, Wells, Nevada; (4) !• cuneata ssp. introg.ressa, Wellington, Utah; (6) !• welshii, Cisco, Utah. 25. 25 . . 20 20 . . . . 15 15 . . ' ' 10 10 ' ' ' ' 5 - - 5 ' - I 3.6 4.0 4,0 4.0 7.6 7.6 2.1 2.1 2.1 2.1 5.6 5.8 1.611.• 311,111.114,614.6 I 1s.s13.1 19.316.4121.1114. Population 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 Character \J1 fruit length fruit width fruit depth number of tubercles (in mm) (in mm) (in mm) (in mm) 52 morphologically in their leaves. Atriplex welshii has leaves which a.re keeled or involute, while!• cuneata ssp. introgressa lacks this trait. A multivariate analysis of fruit characters (see Table 3) of both species yielded a chi square of 39.369 with 12 degrees of freedom. Since this chi square value gives an alpha figure of less than 0.0005, the differences a.re significant. A univariate analysis showed that six of the eighteen measured characters were statis- tically different between the two species. Leaf and habit characters are not different enough to separate the species, but £our of the nine fruit characters show distinct differences. Atriplex welshii can be distinguished from !• cuneata ssp. introgressa by having a shorter and narrower fruit beak which usually has at its base several shoulders and a mu.ch shorter fruit stalk or pedicel. Also, as mentioned above, -A. welshii uniquely has involute or curled leaves. We can conclude then that A. welshii and!• cuneata ssp. introgressa do appear to be genetically distinct entities and should not be grouped into one morphological unit (see Table 20). The northern populations of Atriplex in Utah, Wyoming, Montana, and Western Canada comprise another population group containing abundant variation. To determine whether this variation warranted separating these into separate taxonomic groups, multi- variate and one-way analyses of variance were made for leaf and fruit characters measured in populations sampled throughout much of this area (see Table 21). An analysis of variance of charac- teristics of six southern Wyomingand northern Utah populations showed very little difference among them (see Table 22). However, a considerable number of measured characters appeared to be 53 TABLE20. Comparison of A. welshii and A. cuneata ssp. intro- wigh respect to the means of their morphological characters {all size measurements are in millimeters) Populations Characters A. welshii !• cuneata ssp. introgressa Cisco, Utah Wellington, Utah Plant height 175. 70 162.10 Plant width* 430.00 288.60 Plant depth 391.40 321.40 Leaf length 19.25 21.41 Leaf width 4.45 4.86 Petiole length 2.60 2.16 Leaf 1/w ratio 4.39 4.60 Leaf angle 66.43 65.43 Percent petiole* 12.06 9.10 Fruit length 7.83 1.62 Fruit width 5.58 5.00 Fruit depth 4. 75 4.59 Fruit pedicel length* 0.19 2.54 Fruit beak length* 2.00 3.09 Fruit beak width* 1.07 1.82 Number of shoulders* 3.66 2.34 Number of tubercules 14.83 21.14 Fruit 1/w ratio 1.46 1.60 *Indicates those characters that are significantly different at o< =.05. 54 TABLE21. Popul.ations sampled for analysis of variance of oha.Tac- teristios of Atriplex in Wyoming, Montana, and Alberta, Canada. Population number Location 1 7.0 miles north Rock Springs, Wyoming 2 3.5 miles east Rock Springs, Wyoming 3- 27 miles east Rock Springs, Wyoming 4 24 miles east Wamsutter, Wyoming 5 10 miles north Rawlins, Wyoming 6 10 miles west Casper, V~Joming 7 50 miles north Casper, Wyoming 8 9 miles south Bridger, Montana 9 5 miles south Lovell, Wyoming 10 9 miles south Lovell, Wyoming 11 20 miles south Lovell, Wyoming 12 4 miles south Manderson, Wyoming 13 6 miles west Saco, Montana 14 46 miles north Ferry, Alberta, Canada 15 6 miles north Suffield, Alberta, Canada 16 6 miles south Medicine Hat, ·Alberta, Canada 55 TA:BLE22. One-way a.na.lysis of variance of morphological measure- ments in A. gardneri from Wyomingand northern Utah. (Each mean represents 7 plants per population with one measurement per plants all size measurements are in millimeters.) Population mean Character 1 mile south 23 miles no. 3.5 miles north 11ianila, Utah Manila, Utah Rock Springs, Wyoming Leaf length 11.07 10.57 14.14 Leaf width 5.21 4.50 5. 71 Petiole length 2.7; 2.07 2.01 Leaf 1/w ratio 2.21 2.35 2.52 Leaf angle 49.29 52.14 52.14 Percent petiole 20.64 16.13 14.55 Fruit length 5. 71 4.86 5.64 Fruit width 2.31 2.39 2.37 J!"ruit depth 1.87 2.20 1.79 Pedicel length 0.50 0.43 1.07 Beak length 0.57 0.79 1.29 Beak width 0.57 o. 71 0.86 # terminal points 3.00 3.29 3.71 # tubercules 3.57 10.14 5.86 Fruit 1/w ratio 2.45 2.08 2.35 if-ii-Significant at =.05, F5'36 R>3.6249 56 TABLE22. Continued Population mean F-test 27 miles east 16 miles north 10 miles west Rock Springs, Wyoming Rawlins, Wyoming Casper, Wyoming 10.86 10.64 11. 71 1.6739 3.86 4.57 4.43 1 .9145 1.50 1. 79 2. 71 2.1540 3.01 2.36 2.46 1.4069 59.29 55.00 53.57 2.1913 12.52 14.29 20.46 5.1139** 4.79 6.29 6.14 1.8449 2.23 3.10 3.14 5.0968** -l<·*i-:· 1.64 1.91 2.19 o.8840 0.21 0.64 0.43 1. 7241 1.00 1.36 1.57 3.9187-IHE- 1.07 1.21 1.21 3.9s43-H- 2.43 3.29 3.86 1.2616 6.oo 4.15 6.71 1.0587 2.20 2.06 2.06 0.7038 iE·lHE-"This.significant reading was due to the populations from Rawlins and Casper, Wyoming. 57 statistically different between populations of Montana and those of Alberta (see Table 23). By application of the NewmanKeul Multiple Range Comparison Test, it was determined that the most significantly different characters (i.e., leaf length and width, petiole length, percent petiole, and fruit depth) came from population number 13, near Saco, Montana. When this population is omitted, Canadian populations show a high correlation of characters. When both the Canada-Montana group and the western Wyominggroup were analyzed together (Table 23), it was discovered that most of the measured characters from the Saco, Montana population were not significantly different from those of western Wyomingpopulations. - The revised Canadian group, with the Saco population omitted, shows little within-group morphological variance and appears to remain distinct from the western Wyominggroup with the Saco, Montana, population included in it. This is illustrated below by two examples from the NewmanKeul Multiple Range Test (Fig. 2). Leaf length Leaf width Pop.# 1-7 10 11 13 12 8 9 15 14 16 1-7 13 9 11 10 12 8 14 15 16 Results Fig. 2. NewmanKeul Multiple Range Test for two leaf characters from the!• gardneri populations listed in Table 21. It can be concluded, then, that there appear to be at least two distinct morphological entities in the northern, herbaceous, perennial Atriplex, i.e., one in Alberta, Canada and the other in 58 TABLE23. One-way analysis of variance of morphological measure- ments in different population combinations of A. gardneri (see Table 21 for population source) - Canada-Montana Populations 13, 14, 15, 16 F-values F , 24 3 Leaf length 9.1293-H- (Due to Pop. 13) Leaf width 3.3201* (Due to Pop. 13) Petiole length 4.4392* (Due to Pop. 13) Leaf 1/w ratio 0.5004 Leaf angle 0.0930 Percent petiole 6.6914-lH<-(Due to Pop. 13) Fruit length 4.4671* (Due to Pop. 14) Fruit width 1. 7591 Fruit depth 4.2597* (Due to Pop. 13) Fruit pedicel length 5.7608-ff-lf(Due to Pop. 17) Fruit beak length 2.9627 Fruit beak width 1.7852 Number of shoulders 0.5199 Number of tubercules 8.1316-H Fruit 1/w ratio 0.2709 *Population means are significantly different ato<=.05. *Population means are significantly different atOC=.01. 59 TABLE23. Continued Populations Western Wyoming Canada-Montana & Western Wyoming Populations 1-12 All populations F-values 1'19'60 F15' 108 7.0310~ 2.3460~ 10.1840m'i- 2.4620-IHE- 5.1285-iHE- 2 .1048-iC· 1.1000 0.6393 1.9944 1.6540 5.9734-H- 5.9863-l<-X- 1.1459 1.4457 8.5569ff- 3.4184ff· 4.1607-'ln'<- 3.6558-)(-X, 2.0494* 2.8220-lt-lt 1.5506 3.1364~ 2.2408* 3.4310** 0.9758 0.9968 4.3296-H- 4.3340** 4.84787Hi- 1.6292 60 Wyomingand Montana. Thus, the group which occupies western Wyomingand southwestern Montana will hereaf'ter, in this report, be referred to as!• gardneri. Using a cluster analysis on the populations listed in Table 2, a similarity index was generated together with its pheno- gra.m (Fig. 3) for defining morphological relationships. It is apparent that all twenty-eight populations of this complex of species are more similar than different, i.e., having a similarity index of 53.9 percent. The similarities of each species, however, are not strong. Populations of only four species clustered together: _!. corrµgata, !• cuneata (2n=18), !• cuneata ssp. introgressa, and .!• gardneri (2n=18). Two of these species,!• cuneata ssp. intro- gxessa and !• cuneata (2n=18), contail. only one population each and should thus be eliminated. Populations of the remaining species do show some relatively strong af'finities, i.e., four of the five populations of!• falcata cluster together and show a similarity index of 81.6 percent as do three of the six populations of -A. ga.rdneri at an index value of 78.1 pe~cent. Strong cluster relationships of all 18 para.meters (Table 3) can be observed in the clustering of plants into their respective populations. Fifty-six plants from eight populations were analyzed in the cluster analysis program. From the results illustrated in Fig. 4, many of the plants clustered into their respective popu- lations. In fact, only two out of fifty-six plants clustered outside of their respective species. The cluster analysis program was also used to analyze the leaf and fruit characters, respectively. Fig. 5 shows that the O"I ...a. Fig. 3. PhenogTam of twenty-eight populations of Atriplex clustered by using eighteen leaf, fruit, and habit characters: A. ~eri, 1-7; !• falcata, 8-12; !• tridentata, 13-17; !• co~ata, 18-20; !• welshii, 21-22; !• cuneata2n=36), 23-25; A. cuneata ssp. introgressa, 26; !• ouneata2n=18), 27-28. See Table 2 for specific population identification. 62 N- -. C> I !!- I .... I - I - -. "" .... t- - Ii- - I - I *z 0 - i: C ....::, .. A. . 0 A. -... I i,,.. I ,0 I - I ,.:...... -. I I N...... ..- . I .C') I 0 i i ,0 0\ \Joi Fig. 4. The cluster analysis phenogram of 56 plants from eight widely scattered populations of Atriplex: !• gardneri, plants 1 to 14 with samples 1 to 7 from Lovell, Wyoming, and 8 to 14 from Wamsutter, Wyoming; A. falcata, plants 15 to 28 with samples 15 to 21 from Mud Lake, Idaho, and 22 to 28 from Grouse Creek-; Utah; A. tridentata, plants 29 to 56 with samples 29 to 35 from Ephraim, Utah, 36 to 42 from Salina, Utah, 43 to 49 from Sigurd, Utah, and 50 to 56 from Grantsville, Utah. 64 -... - -iii- -- ...:J-1 I I I .. I - I .... :s; - I I I - I I - -- - . - - . = - !" ·~ # I z ....- 0 -.... ,J-' .. _, I::: - :::, A, .... 0 - A, - - J---1 -·- - I - I -·- .....- - t- I -- - - - I - - . .... -- ,r:- .... I ~...... u "" ... I ...- -· ..,, ...... - . I- = ~ .. ..,, -i,1JDflWI$. . . 0/,o- - - Population + 11 22 9 14 13 JS JO 16 8 17 21 26 6 7 12 JS 19 20 23 25 24 4 3 S 2 27 28 -- LJ T -- --,-- 9 n --,- I I I t I T l:- ·.: a,I ·s TI •• ---- " 71\ 6 I Fig. 5. Phenogram of twenty-eight populations of Atriplex clustered by using leaf characters. !• gardneri, 1-7; !• falcata, 8-12; !• tridentata, 15-17; !• corrugata, 18-20; !• welthii, 21-22; A. V1 cuneata (2n•36), 23-25; !• cuneata ssp. introgressa, 26; !• cuneata (2n•18), 27-28.See Table 2.j °' 66 leaf characters (see Table 3) do contribute to the separation of certain species and appear to have more resolution than the analysis of the entire eighteen characters. In fact,. these leaf characters yielded the complete separation of!• cuneata (2n=18), !• cuneata (2n=36), and!• corrµgata from the rest of the Atriplex subshrub complex. As can also be seen in Fig. 3, only some of the other populations were clustered into their respective species. The measured fruit characters as listed in Table 3, when clustered, did not give any distinctive clustering patterns (see Fig. 6}. Thus, the fruit characters, when used collectively, fail to assist in the separation of the populations into their respective species. Although this cluster analysis does show some similarities, one would think stronger groupings should be present to indicate the relationship of each population to its respective species. This, however, may not be the case at all. While it is true that all populations of each species are closely related, it is also true that each population is genetically distinct; i.e., each population has unique specific characters. It is also true that each popu- lation is more than just a sum total of its morphological expressions; ecological parameters such as latitude, longitude, precipitation, edaphic factors, etc., also influence phenotypes and select out specific genotypes. Through time, the process of natural selection has carved out the unique characters. Thus, even though all popu- lations of each species did not cluster intimately together, the biological affinities are not obviated. As indicated in the discriminant analysis results of Table 24, all eighteen measured variables from Table 3 a.re significantly 0\ -:i Fig. 6. Phenogram of twenty-eight populations of Atriplex clustereQ by using fruit characters: !• gardneri, 1-7; !• falcata, 8-12; !• tridentata, 13-17; !• corrgga.ta, 18-20; !• welshii, 21-22; !• cuneata {2n=36), 23-25; !• cuneata ssp. introgressa, 26; !• cuneata (2n=18), 27-28. See Table 2 for specific population identification. POPULATION * 13 15 14 4 7 6 16 5 17 19 8 11 9 10 '8 12 1 23 25 7 :8 3· : 0 ~•4 26 22 21 90 T ------..,__ T- -.- 80 >- ·-.... .! T ·;·e 70 I 60 O'\ 50 I CD TA:BLE24. A SUllllll8rYof discriminant analysis for nine species in the !• ga.rdneri complex. (All species means are significantly different at C(..~.05) Program .Degrees Number of Proportion Cumulative step Variable entered of F-value variables of total portion of number Freedom included dispersion total dispersion 1 Leaf width F , 972 1 .6303 .6303 7 409.7 2 Leaf angle F , 971 151.5 2 .1129 7 .7432 Fruit width F , 970 105.9 .0913 3 7 3 .a345 Plant height F , ~69 85.4 .0809 .9154 4 7 4 Percent petiole F ,- 968 a3.4 .0555 .9709 5 7 5 6 Leaf length F , 967 1a.3 6 .0169 .9878 7 Petiole length F , 966 4-4.1 .0077 7 7 7 .9955 8 Pedicel length F , 965 41.8 8 .0045 1.0000 7 Fruit length F , 964 .0000 1.0000 9 7 35.9 9 10 # tubercules F , 963 34.1 10 .0000 1.0000 7 11 # shoulders F , 962 11 .0000 1.0000 7 33.9 12 :Beak width F , 961 62.8 12 .0000 1.0000 7 Fruit 1/w ratio F , 960 13 .0000 1.0000 13 7 55.9 Plant width F , 959 21.2 14 .0000 1.0000 14 7 Leaf 1/w ratio F , 958 21.2 15 .0000 1.0000 15 7 16 :Beak length F , 957 12.7 16 .0000 1.0000 7 Fruit depth F , 956 17 .0000 1.0000 17 7 4.3 18 Plant depth FZ' 955 2.6 18 .0000 1.0000 \.0°' 70 different across species; i.e., all F-values are greater than the 0.05 points of the F-distribution. Therefore, in the discriminant analysis, all variables were used to obtain the best separation of the populations. J3y calculation of eigenvalues, using the variance- covariance matrix, determination can be made as to which variables account for most of the variation. The proportion of total dispersion (Table 24), that pa.rt of each eigenvalue to the whole, suggests which characters are yielding the best basis for separation by giving a relative importance percentage in the separation. As can also be seen in Table 24, most of the separation appears to have occurred before step number 8. This is illustrated in Table 25 by contrasting the separation that had occurred by step nine against the total separation in step eighteen. The first eight characters, then, essentially account for the grouping of plants into their respective species. Leaf width is the most discriminating of the eighteen measured characters in separating the 980 plants into 9 species, accounting for 63 percent of the plant grouping (Table 24). The effect of the separation of the first step can be seen in Table 26, as can the effect of each cumulative step through analysis number eight. The second most discriminating character, leaf angle, accounts for 11.29 percent of the plant grouping and the third charac- ter, fruit width, for 9.13 percent (Table 24). Thus, the best characters to separate the nine species are the following: leaf width, leaf angle, fruit width, plant height, percent petiole, leaf length, petiole length, and pedicel length. Five of the eight characters are leaf measurements. This is why, in the cluster TABLE25. The number of plants which were classified into their respective species at steps nine and -.:i..,, eighteen in the discriminant analysis of all species in the!• gardneri complex Step Number 9 Population 1 Population 2 A. cun. !• ~- !• ~- !• ~- !• gar. Totals 2n=3 !• £.!!.. !• !E.• !• .£2£• !• ~- -2n=36 ssp. 1:!!1• 2n=18 2n=18 - !• &!:!• 2n=36 148 13 0 0 2 13 6 5 23 210 !• I!!• 0 166 5 4 0 0 0 0 0 175 !• !E.• 0 15 137 19 4 0 0 0 0 175 !• £2!.• 0 4 1 98 1 1 0 0 0 105 !• !!!!.• 2 5 9 0 53 0 1 0 0 70 !• ~• 2n=36 7 0 0 0 0 95 1 2 0 105 !• ~• ssp. 1 0 0 0 3 0 31 0 0 35 !• ~• 2n=18 5 0 0 0 0 3 0 62 0 70 !• &!:!.• 2n=18 3 2 0 0 0 0 0 0 30 35 TABLE25. Continued Step Number 18 Population 1 Population 2 A.~• A. cor. A. cun. !• ~- A. cun. !.• ~- Totals -2n=3 !• .!!!• !• .:51. - - !.• ru,. -2n=36 ssp. M• -2n:ra 2n=18 !• .m,. 2n=36 164 11 6 2 0 13 0 4 10 210 !• .!:!J.. 0 174 1 0 0 0 0 0 0 175 !• fil• 0 3 163 3 6 0 0 0 0 175 !• .£2!:• 1 0 1 103 0 0 0 0 0 105 -A. - wel. 3 3 2 0 60 0 2 0 0 70 -A. -cun. 2n=36 4 0 0 0 0 101 0 0 0 105 --A. cun. ssp - int. 0 1 0 1 0 0 33 0 0 35 !• ~• 2n=18 3 0 0 0 0 4 0 63 0 70 !• e,. 2n=18 1 1 0 0 0 0 0 0 33 35 -.J I\) -.J TABLE26. The number of plants which were classified into their respective species in each step of the first eight steps in the discriminant analysis of all species in the!.• gardneri complex (each step "" includes all those preceding); see also Table 24 Step 1: Leaf length (proportion of total dispersion--63.03%) Population 1 Population 2 A. cun. A.~• A. !• ~- A.~• !.• .E• Totals -2n=3 !• ~- m,. !• -22!:• !.• W.• -2n=36 ssp. B!l• 2n=38 2n=18 !.• 6!:£.• 2n=36 46 0 4 1 2 65 24 14 54 210 A. £!!• 2 6 14 46 53 4 34 0 16 175 !.• tri. 2 2 17 18 79 0 39 0 18 175 !• .25.• 0 0 0 103 2 0 0 0 0 105 .!• ~- 0 1 6 11 32 0 19 0 1 70 !• .2B!!• 2n=36 31 0 0 0 0 43 0 6 25 105 -A. --cun. ssp int. 0 0 3 1 10 0 17 0 4 35 !.• .2Sl• 2n=18 0 0 0 0 0 16 0 54 0 70 !.• gar. 2n=18 4 0 3 0 0 0 5 0 23 35 TABLE26. Continued Step 2: Leaf angle (proportion of total dispersion--11.29%) Population 1 Population 2 A. cun. A. cun. !• gar. A. tri. A. wel • !• ~· !• m,. Totals 2n=36 !• i!!• - - !• £2!.• .... - -2n=36 ssp. l:!li• -2n-;;fe' 2n=18 !• gar. 2n=36 123 0 1 4 0 16 32 11 23 210 -A. -fal. 0 82 37 5 19 0 10 0 22 175 --A. tri. 0 60 53 14 6 0 23 0 19 175 -A. -cor. O 0 0 90 14 1 0 0 0 105 !• .!!.!• 0 37 10 1 0 0 22 0 0 70 !• ~• 2n=36 22 0 0 0 0 79 1 3 0 105 -A. -cun. ssp -int. 1 1 9 1 0 0 23 0 0 35 !• ~- 2n=18 12 0 0 0 0 3 0 55 0 70 !• E• 2n=18 0 8 0 0 0 0 1 0 26 35 -:i \Jl TABLE26. Continued Step 3: Fruit width (proportion of total dispersion--9.13%) Population 1 Population 2 A. cun. A.~• !• ~- A. cun. !• ~- Totals -2n=3 !• fi:!• !• !E:.• !• -2.2!:• !• !!tl.· -2n=36 ssp. !Ui• -2n:T'a 2n=18 !• gar. 2n=36 129 3 4 14 0 16 8 10 26 210 !• fi:!. 1 135 6 9 0 0 0 0 24 175 !• .E:!• 1 25 75 24 41 0 5 0 4 175 !• £2£• 0 3 12 86 1 1 2 0 0 105 !• ?!tl· 0 3 18 2 29 0 18 0 0 70 !• ~• 2n=36 12 0 0 0 0 86 3 4 0 105 --A. cun. ssp -int. 0 0 11 0 4 0 20 0 0 35 !• ~• 2n=18 12 0 0 0 0 2 0 56 0 70 !• .e,. 2n=18 0 7 1 0 0 0 0 0 27 35 TABLE26. Continued Step 4: Plant height (proportion of total dispersion--8.09%) Population 1 Population 2 A.~• A. cun. A. cun. A. cun. !• -2n=3 !• .!!:!.• !• itl• !• 22!:• !• ~. -2n=36 ssp. int. -2n;:j'a 2n=18m• Totals !• E• 2n=36 130 4 9 9 0 17 6 8 27 210 !• .!!!.• 1 145 5 3 2 0 0 0 19 175 !• fil• 0 15 122 14 16 0 5 0 3 175 !• -22!:• 0 1 1 96 3 1 3 0 0 105 !• ~. 0 9 4 3 32 0 22 0 0 70 -A. -cun. 2n=36 12 0 0 0 0 86 3 4 0 105 --A. oun. ssp - int. 0 2 0 1 8 0 24 0 0 35 !• ~• 2n=18 12 0 0 0 0 2 0 56 0 70 !• .6'£• 2n=18 1 4 0 0 0 0 0 0 30 35 -.:i O'\ -3 -3 TA:BLE26. Continued Step 5: Percent petiole (proportion of total dispersion-55.5%) Population 1 Population 2 A. e_. A. cun. A. oun. !• ~- !• ,e:. Totals 2n=36 !• .!'!d-.·!• ill.• !• £2!:• !• !!!!• -2n=36 ssp- •- .i!!i• 2n=18 2n=18 !• gar. 2n=36 141 8 2 6 0 14 6 1 26 210 !• !!!• 0 169 2 2 0 0 0 0 2 175 !• ill.• 1 15 134 15 8 0 2 0 0 175 !• .£2.£• 0 2 1 94 3 1 4 0 0 105 !• ~- 2 8 7 0 24 0 28 0 1 70 -A. -cun. 2n=36 9 0 0 0 0 90 3 3 0 105 -A. --cun. ssp int. O 1 0 3 7 0 22 0 2 35 -A. -cun. 2n=18 6 0 0 0 0 3 0 61 0 70 !• .&!:£• 2n=18 2 1 0 0 0 0 0 0 32 35 TABLE26. Continued Step 6: Leaf length (proportion of total dispersion-1.69%) Population 1 Population 2 A.~• A. cun. A. cun. !• cun. !• E• Totals -2n=3 !• ~. !• s!_. !• .£2£• !• l!!!!· -2n=36 ssp.- -l:!!1• 2n=18 2n=18 !• gar. 2n=36 142 14 1 1 0 14 6 6 26 210 -A. -£al. 0 156 9 10 0 0 0 0 0 175 !• !E:.• 0 17 130 17 9 0 2 0 0 175 !.• ~- 0 0 1 101 0 1 2 0 0 105 !• l!!!!· 1 7 6 0 25 0 30 0 0 70 !• £!fil• 2n=16 7 0 0 0 0 92 3 3 0 105 !• £!fil• ssp int. O 1 1 0 8 0 23 0 0 35 !• £!fil• 2n=18 6 0 0 0 0 3 0 61 0 70 !• S.• 2n=18 2 1 0 0 0 0 0 0 32 35 0) -.::i TABLE26. Continued '° Step 7: Petiole length (proportion of total dispersion--0.77%) Population 1 Population 2 A.~• A. cun. !• ~- A. C\lll. !• .s!:'£• Totals -2n=3 !• !!!• !• tri. !• .Q2!.• !• ~- -2n=36 ssp • .!!li• -2n;:je 2n=18 !• m,. 2n=36 135 14 1 0 0 17 8 8 27 210 !• !!!.• 0 161 9 5 0 0 0 0 0 175 !• fil• 0 17 132 16 8 0 2 0 0 175 !• ~- 0 3 1 96 0 1 4 0 0 105 !• l!!l· 2 6 8 0 26 0 28 0 0 10 -A. -cun. 2n=36 1 0 0 0 0 93 2 3 0 105 --A. cun. ssp - int. 0 1 1 0 7 0 24 0 2 35 -A. -cun. 2n=18 5 0 0 0 0 3 0 61 1 70 !• .m,. 2n=18 3 1 0 0 0 0 0 0 31 35 TABLE26. Continued Step 8: Pedicel length (proportion of total dispersion--0.45%) Population 1 Population 2 A.~• A. cun. A. cun. !• .2:!!!.• !• .m,. -2n=3 !• ~- !• .fil• !• -2.2!:• !• .!'!.tl· -2n=36 ssp. int. 2n=18 2n=18 Totals !• S'S.• 2n=36 144 13 0 1 2 13 5 8 24 210 -A. -fal. 0 162 7 3 2 0 1 0 0 175 !• .51. 0 14 133 17 10 0 1 0 0 175 -A. -cor. 0 3 1 96 2 1 2 0 0 105 -A. -wel. 3 5 9 0 51 0 2 0 0 10 !• .2:!!!.•2n=36 1 0 0 0 0 93 2 3 0 105 --A. cun. ssp - int. 0 1 0 0 3 0 30 0 1 35 !• ~• 2n=18 5 0 0 0 0 3 0 61 1 10 !· §!:!. 2n=18 3 2 0 0 0 0 0 0 30 35 0) 0 81 analysis of the leaf characters, the resolution was so good. When the twenty-eight populations listed on Table 2 were clustered according to the eight most discriminating characters, twenty of the twenty-eight hierarchal relationships were the same as the results of the leaf cluster program, although the similarity index differed slightly (see Fig. 7). The discriminant analysis program also computes canonical correlations and plots an optical two-dimensional canonical dispersion. Fig. 8 illustrates this two-dimensional canonical picture of the relationship of all these subshrub species. There appear to be definite affinities of some of the species and rather disjunct relationships for the others. For instance,!• cuneata (both diploids and tetraploids) and!• corrugata are distinct from f!.• tridentata. This relationship can also be observed in the cluster phenograms of Figs. 3, 5, and 7. Furthermore, this also suggests that!• corrugata is disjunct from all other species except!• falcata, and!• gardneri is disjunct from!• tridentata, !• welshii, and!• corrugata. As suggested above, however, these relationships can~ be verified from the cluster analysis pheno- gram (Figs. 3, 5, and 7). Nevertheless, there appears to be a general pattern in the relationship of these species. The narrow leaved species are distinct from the broader leaved_!• cuneata, and the disjunction is bridged by!,. gardneri. The two-dimensional diagrams also suggest affinities between some of the species. There appears to be a close rela- tionship of!• welshii, !• falcata, and!• cuneata ssp. introgressa to!• tridentata (see Figs. 8 and 9). This is understandable Fig. 7. Phenogram of twenty-eight populations of Atriplex clustered as to the discriminant analysis results in Table 24. Parameters entered: leaf width, leaf angle, fruit width, plant height, percent petiole, leaf length, petiole length, and pedioel length. (!. ~eri~ 1-7; !.• falcata, 8-12; !.• tridentata, 13-17; !.• oo~ta~ 18-20; !.• welshii, 21-22; !• euneata2n=36, 23-25; !• ouneata ssp. introg.ressa, 26; !• euneata 2n=18, 27-28. See Table 2 for specific population identification.) 83 -0 -~ ..- I- ... I I N" N i:::: I i.- - .,,- C') I ..,. C'il .,, N I C') N fl: .,, z 0 - C"I cc.:: - ..::::, - a. 0 " I a. ,0 ,0 N I I H- -" 0- 00 i-~ °' "' I - I C') ,0- - ..,.- I- 0 0 0 0 °' 00 ,0 0) -i:=-. Fig. 8. Two-dimensional dispersion of canonical variables of the following species: (A)!• fardneri (2n=36), {B) !• falcata, (C) !• tridentata, {D) A. coITTta, {E) !• welshii, {F) !• cuneata 2n=36), (G) !• cuneata ssp. introgressa, (H) !• cuneata "{'2n=18, and (I)!• gardneri (2n=18). The X axis represents the first canonical variable and the Y axis the second canonical variable. The species canonical means are indicated by a centrally located dot. 5.5 4.8 4.1 C 3.5 2,8 2.1 1.5 0.8 0.1 -0.5 -1.2 -1.9 -2.5 -3.l -3.9 -4.5 CD -11.2... -9.'1 -7.2 -5.2 -3.2 -1.2 0.8 2.8 4.8 \JI 86 ATRIPLEX TRIOENTATA Fig. 9. Two-dimensional diagram of the dispersion of the canonical variables of the narrow leaf species in the!• gaxdneri complex (extracted from Fig. 8). 87 because these are primarily all of the narrow leaved species whieh have upright growth habits. Also, because!• tridentata expresses the most morphological diversity, it has the broadest dispersion in Fig. 9. There also appears to be a close relationship between the diploid species and tetraploid races of each. In this study, two tetraploid populations were analyzed separately from their diploids, i.e., two of the five populations of!• cuneata were diploids as was one of seven populations in!• gardneri. Figs. 8 and 10 show the relationship of the diploids and tetraploids. The discriminant analysis program was also used to analyze selected species. It identified which measured characters (Table 3) could be used to separate each of the ecotypes of!• gardneri, A. cuneata, !• corrua;ata, and!• tridentata as well as provide an indication of their morphological diversity. It appears that.!• gardneri characters are relatively variable, because the seven following steps were required for total dispersion: plant height, leaf length, leaf angle, plant width, percent petiole, fruit 1/w ratio, and plant depth (see Tables 27 .and 28). This is also depicted in the phenogram in Fig. 11. The populations of!• cuneata can quite easily be separated by using the leaf length and width characters along with the fruit beak width (see Tables 29 and 30). Fig. 12 indicates that the diploids (Populations D and E) have a dis- persion pattern which is distinct from the tetraploids (Populations A, B, and C). Atriplex corrugata is probably the least variable of all the species in that only fruit width and depth are the characters required for their separation, and nearly one-half of the the 88 ATRIPLEX GARDNERI 2n= 36 A ATRIPLEX ATRIPLEX CUNUTA CUNEATA 21= 18 2n= 36 B Fig. 10. Two-dimensional dispersion of the canonical variables of two diploid species and their tetraploids: (A)!• gardneri and {B) !• cuneata (extracted from Fig. 8). TABLE 27. The discriminant analysis summaryfor seven populations of!• .s:,a.rdneri Program Degrees Number of Proportion Cumulative step Variable entered of F-value variables of total portion of number freedom included dispersion total dispersion 1 Plant height F6, 238 10.02 1 .3570 .3570 2 Leaf length 2 F6, 237 73.19 .3313 .6882 3 Leaf angle F6, 236 31.51 3 .1216 .,8099 Plant width 4 F6, 235 29.84 4 .0978 ..9076 5 Percent petiole F6, 234 24.21 5 .0613 .9689 6 Fruit 1/w ratio F6, 233 20.69 6 .0311 .9999 Plant depth 7 F6, 232 19.28 7 .0000 1.0000 8 Leaf 1/w ratio 8 F6, 231 19.53 .0000 1.0000 9 Fruit length F6, 230 10.52 9 .0000 1.0000 10 Fruit depth F6, 229 7.95 10 .0000 1.0000 Leaf width F , 228 11 6 6.08 11 .0000 1.0000 Beak length 12 F6, 227 6.52 12 .0000 1.0000 13 # shoulders F6, 226 3.64 13 .0000 1.0000 14 # tubercules F6, 225 3.56 14 .0000 1.0000 15 Pedicel length F6, 224 3.81 15 .0000 1.0000 16 Beak width F6, 223 3.10 16 .0000 1.0000 17 Fruit width F6, 222 4.64 17 .0000 1.0000 18 Petiole length F , 221 3.33 18 .0000 1.0000 6 CX> \D 90 TABLE28. The number of plants which were classified into their respective populations at steps seven and eighteen in the discrim- inant analysis of seven populations of!• ga;rdneri Step number seven Population 1 Population 2 Lovell, Wamsutter, Saco, Wyoming Wyoming Montana Lovell, Wyoming 31 0 0 Wamsutter, Wyoming 0 32 2 Saco, Montana 0 0 32 N. Casper, Wyoming 0 1 3 Sweetgrass, Montana 0 0 7 w. Casper, Wyoming 0 0 0 Red Desert, Wyoming 0 0 0 Step number eighteen Population 1 Population 2 Lovell, Wamsutter, Saco, Wyoming Wyoming Montana Lovell, Wyoming 32 0 0 Wamsutter, Wyoming 0 32 1 Saco, Montana 0 0 32 N. Casper, Wyoming 0 0 0 Sweetgrass, Montana 0 0 1 w. Casper, Wyoming 0 0 0 Red Desert, Wyoming 0 0 0 91 TABLE28. Continued Step number seven Population 1 Totals N. Casper, Sweetgrass, w. Casper, Red Desert, Wyoming Montana Wyoming Wyoming 0 0 0 4 35 0 0 0 1 35 0 3 0 0 35 30 1 0 0 35 0 27 1 0 35 0 1 32 2 35 0 0 1 34 35 Step number eighteen Population 1 Totals N. Casper, Sweetgrass, w. Casper, Red Desert, Wyoming Montana Wyoming Wyoming 0 0 0 3 35 0 0 0 2 35 0 3 0 0 35 35 0 0 0 35 0 34 0 0 35 0 0 35 0 35 0 0 0 35 35 \0 I'\) Fig. 11. Two-dimensional diagram of the dispersion of the canonical variables of seven populations of!• gardneri. The populations are as follows: (A) 20 miles south Lovell, Wyoming, (B) 24 miles east Wamsutter, Wyoming, (C) 6 miles west Saco, Montana, (D) 50 miles north Casper, Wyoming, (E) 6 miles south Sweetgrass, Montana, (F) 50 miles west Casper, Wyoming, and (G) 1 mile east Red Desert, Wyoming. Each population canonical mean is indicated by a centrally located dot. The X and Y axes represent the first and second canonical variables, respectively. 3.9· 3.3 2.6 1.9 • ,, --. I ,.._ I I • F 1.31 0.6 I 7~ • -0.7, . •• ~"'• -0.71 B -1.4 \ \ D ·2.1 -2.7, -3.4 -4.1 _ -4.7,- ·A -5.4 -6.1 ... \J) . . . . .- . . 9.4 7.1 5.4 3.4 1.4 0.6 2.6 4.6 6,6 TABLE29. The discriminant a.na.1.ysis summary for!• cuneata Program Degrees Number of Proportion Cumulative step Variable entered of F-value variables of total portion of number freedom included dispersion total dispersion Leaf length F , 170 197.0052 1 .8294 .8294 1 4 2 Beak width F , 169 25.9866 2 .1093 4 .93e7 Leaf width F , 168 20.3073 .0492 .9879 3 4 3 Plant width F , 167 19.1425 .0121 1.0000 4 4 4 Plant height F , 166 10.0761 .0000 1.0000 5 4 5 6 # shoulders F , 165 11.3452 6 .0000 1.0000 4 Percent petiole F , 164 9.0942 7 .0000 1.0000 7 4 8 Petiole length F4-' 163 5.1521 8 .0000 1.0000 Leaf angle F , 162 4.7669 .0000 1.0000 9 4 9 10 Plant depth F , 161 3.8718 10 .0000 1.0000 4 11 Leaf 1/w ratio F , 160 2.8100 11 .0000 1.0000 4 12 # -tubercules F , 159 2.3996 12 .0000 1.0000 4 Fruit length F , 158 2.1889* 13 .0000 1.0000 13 4 Beak length F , 157 2.1632* 14 .0000 1.0000 14 4 Fruit depth F , 156 2.1994* 15 .0000 1.0000 15 4 16 Fruit width F , 155 1.3987* 16 .0000 1.0000 4 Fruit 1/w ratio F , 154 o.6471* .0000 1.0000 17 4 17 18 Pedicel length F~, 153 o.6257* 18 .0000 1.0000 \0 *!21 signii'icant at o(=.05. 95 TilLE :;o. The number of plants which were classified into their respective populations at steps four, twelve, and eighteen in the discriminant analysis of five Utah populations or -A. cuneata Step number~ Population 1 Population 2 Totals lllil.ery Green River Price Bonanza* Bonanza* Emery 26 1 8 0 0 35 Green River 0 25 3 0 7 35 Price 10 0 25 0 0 35 Bonanza* 0 0 0 33 2 35 Bonanza* 0 1 1 3 30 35 Step number twelve Population 1 Population 2 Totals :Emery Green River Price Bonanza* Bonanza-IE-ff- Emery 25 2 8 0 0 35 Green River 0 35 0 0 0 35 Price 11 0 24 0 0 35 Bonanza* 0 0 0 34 1 35 Bonanza* 0 0 0 2 33 35 Step number ei~hteen Population 1 Population 2 Totals Emery Green River Price Bonanza* Bonanza* Emery 27 1 7 0 0 35 Green River 0 35 0 0 0 35 Price 10 0 25 0 0 35 Bonanza* 0 0 0 33 2 35 l3onanza* 0 0 0 1 34 35 *3 miles south Bonanza, Utah. . iHt-16miles south Bonanza, Utah. '°0\ Fig. 12. Two-dimensional diagram of the dispersion of the canonical variables of five popula- tions of!• cuneata. The populations a.re as follows: (A) 5 miles south ~ery, Utah, (B) 12 miles east Green River, Utah, (C) 5 miles north Price, Utah, (D) 3 miles south Bonanza, Utah, and {E) 16 miles south Bonanza, Utah. Each population canonical mean is indicated by a centrally located dot. The X and Y axes represent the first and second canonical variables, respectively. 7.4 6,7, 6.1 5.4 4.7 4.1 3.4 2.7 ·B 2.1 1.4 0.7 0.1 0.6 1,3 1.9 2.6 -.3 -8.6 -6.6 -4.6 -2.6 -0.6 1.4 3A SA 7.4 '° 98 eighteen measured characters are not statistically different (Tables 31 and 32). The dispersion picture of!• gorrugata shows no over- lapping of the populations, which is most probably due to the striking differences in fruit width and depth (see Fig. 13). Atriplex tridentata, although quite variable as a species, requires only four characters to account for the discriminant total disper- sion; i.e., plant height, leaf angle, leaf width, and plant depth (see Tables 33 and 34). TABLE31. The discriminant analysis summaryfor A• corrwmta Program Degrees Number of' Proportion Cumulative step Variable entered of F-value variables of total portion of number Freedom included dispersion total dispersion F , 102 1 Fruit depth 2 112/9946 1 • 7541 .7541 F , 101 2 Fruit width 2 37.0217 2 .2458 .9999 3 Beak width F2, 100 18.0860 3 .0001 1.0000 4 Leaf angle F2, 99 35.9873 4 .0000 1.0000 5 Beak length F2, 98 17. 7915 5 .0000 1.0000 6 Petiole length F2, 97 12.6776 6 .0000 1.0000 7 Plant height F2, 96 5.1729 7 .0000 1.0000 8 Leaf 1/w ratio F2, 95 3.0246* 8 .0000 1.0000 Plant width 9 F2, 94 3.1817 9 .0000 1.0000 10 Plant depth F2' 93 11.9766 10 .0000 1.0000 11 Percent petiole F2, 92 3.4163 11 .0000 1.0000 12 Pedicel length F2, 91 2.5029* 12 .0000 1.0000 Leaf length 13 F2 , 90 0.9471* 13 .0000 1.0000 14 # shoulders F2, 89 1.2418* 14 .0000 1.0000 F , 88 15 Fruit 1/w ratio 2 0.7229* 15 .0000 1.0000 16 16 # tubercules F2, 87 1.0513* .0000 1.0000 Leaf width F , 86 17 2 0.4911* 17 .0000 1.0000 Fruit length 18 18 F2, 85 0.0393* .0000 1.0000 *!21 significant ato<=.05. '° 100 TABLE32. The number of plants which were classified into their respective populations at steps three, eight, twelve, and eighteen in the discriminant analysis of all populations of!• corrµgata Step number three Population 1 Population 2 Totals Wellington, Utah Cisco, Utah Vernal, Utah Wellington, Utah 33 2 0 35 Cisco, Utah 6 28 1 35 Vernal, Utah 3 0 32 35 Step number ei~ht Population 1 Population 2 Totals Wellington, Utah Cisco, Utah Vernal, Utah Wellington, Utah 35 0 0 35 Cisco, Utah 3 32 0 35 Vernal, Utah 0 0 35 35 Step number twelve Population 1 Population 2 Totals Wellington, Utah Cisco, Utah Vernal, Utah Wellington, Utah 35 0 0 35 Cisco, Utah 1 34 0 35 Vernal, Utah 0 0 35 35 Step number ei~hteen Population 1 Population 2 Totals Welline;ton, Utah Cisco, Utah Vernal, Utah Wellin&ton, Utah 35 0 0 35 Cisco, Utah 1 34 0 35 Vernal, Utah 0 0 35 35 ...... 0 Fig. 13. Two-dimensional diagram of the dispersion of the canonical variables of three popu- lations of!• corruga.ta. The populations are as follows: (A) 1 mile south Wellington, Utah, (B) 5 miles south Cisco, Utah, and (c) 3 miles northeast Vernal, Utah. F.ach population canonical mean is indicated by a centrally located dot. The X and Y axes represent the first and second canonical variables, respectively. 3.0 2.5 2.01 . B 1".5 I \ I 1.0 0.5J I .A o.o -0.5 -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5. ------·--····______,,..,..,...... 0 -7.5 -6.0 -4.5 -3.0 -1.5 o.o 1.5 3.0 4.5 N T.ABLE33. The discriminant analysis summary for!• tridentata Program Degrees Number of Proportion Cumulative step Variable entered of F-value variables of total portion of number freedom included dispersion total dispersion 1 Plant height F , 170 266.9204 1 .7124 .7124 4 2 Leaf angle F , 169 32.8567 2 .1518 .8642 4 Leaf width F , 168 26.4041 .0987 .9629 3 4 3 Plant depth F , 167 14.2383 4 .0371 1.0000 4 4 Fruit width F , 166 11.0201 .0000 1.0000 5 4 5 6 Percent petiole F , 165 11.2605 6 .0000 1.0000 4 Plant width F , 164 11.1763 .0000 1.0000 1 4 1 8 # shoulders F4-' 163 7.5258 8 .0000 · 1.0000 Beak width F , 162 10.8206 .0000 1.0000 9 4 9 10 Pedicel length F , 161 6.6171 10 .0000 1.0000 4 11 tubercules F , 160 5.6476 11 .0000 1.0000 If 4 12 Leaf 1/w ratio F , 159 4.1422 12 .0000 1.0000 4 Fruit length F , 158 4.1038 13 .0000 1.0000 13 4 Beak length F , 157 1. 7214* 14 .0000 1.0000 14 4 Leaf length F , 156 1. 7184* 15 .0000 1.0000 15 4 16 Fruit depth F , 155 1.3746* 16 .0000 1.0000 4 Fruit 1/w ratio F , 154 1.3592* .0000 1.0000 17 4 17 18 Petiole length F~, 153 0.9449* 18 .0000 1.0000 0 V-1 *1!21 significant at a<=.05. 104 TABLE34. The number of plants which were classified into their respective populations at steps four, thirteen, and eighteen in the discriminant analysis of all populations of!• tridentata Step number~ Population 1 Population 2 ------Totals Ephraim* Salina* Sigurd* Grantsville* Austin** Ephraim* 25 5 0 5 0 35 Salina* 0 28 0 7 0 35 Sigurd* 0 0 35 0 0 35 Grantsville* 5 13 0 16 1 35 Austin** 0 0 0 1 34 35 Step number thirteen Population 1 Population 2 Totals .Elphraim*Salina* Sigurd* Grantsville* Austinff Ephraim* 32 2 0 1 0 35 Salina* 1 30 0 4 0 35 Sigurd* 0 0 35 0 0 35 0 3 0 32 0 35 Austin•:HC- 0 0 0 1 34 35 Step number e~hteen Population 1 Population 2 ------Totals Ephraim* Salina* Sigurd* Grantsville* Austin-!H.- Ephraim* 33 1 0 1 0 35 Salina* 2 31 0 2 0 35 Sigurd* 0 0 35 0 0 35 Grantsville* 0 4 0 31 0 35 Austin** 0 0 0 0 35 35 *Utah **Nevada CHA.PrERIII CYTOLOGICALSTUD!m Materials and Methods Cytological examinations were made primarily from squashes of somatic cells derived from root-tip meristems. Fruits were germinated on moistened germination pads in plastic petri dishes. The entire germinant was harvested between 12 noon and 2 p.m. and treated with colchicine (1 mg/ml) for one hour at room temperature and then stored overnight at 4° c. The following morning the col- chicine solution was discarded and the germinants, after rinsing, were fixed in acetic-alcohol (1:3) for 24 hours. The root-tips were then hydrolyzed in 1 N HCLfor 4 to 5 hours and stored in 70 percent ethanol until analyzed. The apical meristem of each processed root-tip was excised and stained in a drop of acetocar- mine. The excess stain was removed and the root-tip smeared in a small drop of Hoyer•s Solution, yielding a semi-permanent slide. The chromosome preparations were examined with a Zeiss, phase- contrast, microscope. Photomicrographs were taken with a Nikonomat Camera using Kodak high copy contrast film. Karyotyping was completed from 8 x 10 inch photographic prints using precision calipers. 105 106 Results and Discussion Ve~ little work has been done on the cytology of the perennial subshrubs in the genus Atriplex. Chromosomenumbers of only two populations ha.ve been reported to date (:Bassett and Crompton, 1971 and Johnson, 1975), with the ex~eption of two abstracts by Pope and Stutz (1974) and Pope (1975). Bassett and Crompton noted tha.t a.population of -A. tridentata from Walden, Jackson County, Colorado, had a chromosome number of 2n-54. Johnson reported a population of Nuttall's saltbush (most likely!• gardneri) from nea.-r :Bridger, Montana, with a chromosomal count of 2n•18; his actual count was 2n•16 and 17. The cause :for so little work beillg completed on this complex is most likely the lack of a proper technique in.working with the small, numerous chromosomes. After a yea.-r of trial and error and, then, only with the assistance of D:r. Gordon Livillgston (then a postdoctoral student at Brigham Young University under the direction of Dr. Howard Stutz), was a workable technique devised. After the analysis of 89 populations and hundreds of plants, it was found that the species in the!• ga.:rqneri complex form a polyploid series with three known chromosome levels--diploids, tetraploids, and hexaploids. As reported by Darlington and Wylie (1955), the base chromosome number for Atriplex from which this polyploid series a-rose is n•9. The cytological results of mitotic root-tip studies a-re recorded in Table 35. The chromosome number of each sepa.-rate population was con£1:rmed with a minimum of at least two good slide prepa.-rations with several countable cells on each slide so as to 107 T.A:BLE35. Oytological analysis of the subshrubs in the genus Atriplex Chromosome Species and location number (2n) !• acanthocarpa Delicias, Chihuahua, Mexico 18 Cuatro Cienegas, Coahuila, Mexico 18 50 miles west Juarez, Coahuila, Mexico 18 San Bobertas Jct., HU:evoleon, Mexico 36 !• corrupta 5 miles south Cisco, Grand, Utah 1 mile east Thompson, Grand, Utah 7 miles east Thompson, Grand, Utah 1 mile north Moore, Emery, Utah 1 mile south Wellington, Carbon, Utah A•cuneata Price, Carbon, Utah 18 Price, Carbon, Utah 27 Price, Carbon, Utah 36 10 miles south Price, Carbon, Utah 36 10 miles south Price, Carbon, Utah 27 1 mile south Wellington, Carbon, Utah 36 3 miles south Bonanza, Uintah, Utah 18 16 miles south :Bonanza, Uintah, Utah 18 5 miles south Cisco, Grand, Utah 36 10 miles northeast Harley Dome, Grand, Utah 36 5 miles south Hanksville, W~e, Utah 36 Near Shiprock, San Juan, NewMexico 36 A• cuneata ssp. introgressa 1 mile south Wellington, Carbon, Utah 18 10 miles south Price, Carbon, Utah 18 108 TABLE35. Continued Chromosome Species and location number {2n) !• cuneata ssp. introgressa 10 miles south Price, Carbon, Utah 27 17 miles south Price, Emery, Utah on Hwy u.s. 6-50 18 Carbon-Emery County Line, Utah on Hwy u.s. 6-50 36 !• falcata East Desert Mountains, Juab, Utah 18 West Desert Mountains, Juab, Utah 18* East Jericho, Juab, Utah 18 8 miles southeast Woodruff, Rich, Utah 18* 12 miles south Grouse Creek, Box Elder, Utah 18 Dally Varden, White Pine, Nevada 18 Leonard Creek Ranch,.Humboldt, Nevada 18 27 miles west Austin, Churchill, Nevada 18 20 miles south Wells, Elko, Nevada 18 10 miles south Montello, Elko, Nevada 18 8 miles west Mud Lake, Jefferson, Idaho 36 4 miles west Lone Pine, Clark, Idaho 18 Flook Lake, Hart Antelope Refuge, Lake, Oregon 18 Galahad, Alberta, Canada 18 7.5 miles west Hanna, Alberta, Canada 18* !• ga.rdneri 3 miles north :Baggs, Uinta, Wyoming 36 4.3 miles east Lyman,Uinta, Wyoming 36 Lovell, Big Horn, Wyoming 36 1 mile east Rock Springs, Sweetwater, Wyoming 36 7 miles north Rock Spr:i..ngs, Sweetwater, Wyoming 36 1 mile east Red Desert, Sweetwater, Wyoming 18 27 miles east Rock Springs, Sweetwater, Wyoming 18* South Laramie, Albany, Wyoming 18 109 TABLE:35. Continued Species and location Chromosome number (2n) !• gardneri 16 miles north Rawlins, Carbon, Wyoming 36 50 miles south Casper, Natrona, Wyoming 36 79 miles west Casper, F:remont, Wyoming 36 Wyoming-South Dakota Border on HwyU.S. 95 36 5 miles north Ha.nila, Daggett, Utah 36 23 miles north Ivfanila, Daggett, Utah 36 Roundup, Musselshell,- Montana 36 6 miles west Saco, Phillips, Montana 36 & 54 20 miles north Malta, Phillips, Montana 36 5 miles south :Bridger, Carbon, Montana 36 3 miles east Glendive, Dawson, Montana 36 15 miles northMiles City, Custer, Montana 36 !• obova.ta Winslow, Navajo, Arizona 36 Winslow, Navajo, Arizona 54 35 miles south Page, Coconino, Arizona 0 54 Farmington, San Juan, New Mexico 54 Shiprock, San,JU.a.1;1,New Mexico 36 Shiprock, Sa.n Juan, :HewMexico 54 Sa.n Ysidro, Sandoval, New Mexico 36 Za.ca.tecas, Zaca.tecas, Mexico 18 !• tridentata Wellington, Carbon, Utah 54 4 miles west Ephraim, Sanpete, Utah 54 1 mile north Grantsville, Tooele, Utah 54 15 miles south Fish Springs, Juab, Utah 54 Partoun, Millard, Utah 54 Eskda.le, Milla.rd, Utah 54 110 TABLE 35,. Continued Species and location Chromosome number (2n) !• tridentata 3 miles south Pa.inter Springs, Milla.rd, Utah 36 1 mile east Goshen, Utah, Utah 54 Carbon-Emery County Line, Utah on Hwy u.s. 6-50 54 1.5 miles south Sigurd, Sevier, Utah 54 1.5 miles north Salina, Sevier, Utah 54 Near Ouray, Uintah, Utah 54 5 miles west Knolls, Tooele, Utah 54 5 miles west Knolls, Tooele, Utah 45 :Burley, Cassia, Ida.ho 54 Grandview, Owyhee, Idaho 54 2 miles north Montello, Elko, Nevada 54 27 miles west Austin, Churchill, Nevada 54 3.5 miles west Rock Springs, Sweetwater, Wyoming 54 !• welshii 5 miles south Woodside, Carbon, Utah 18 12 miles south Woodside, Carbon, Utah 18 8 miles east Green River, E:nery, Utah 18 12 miles east Green River, E:nery, Utah 18 5 miles south Cisco, Grand, Utah 18 Shiprock, San Juan, NewMexico 18 *Populations containing specimens that showed endoploidy or doubling of the chromosome complement of a small percentage of the somatic cells. 111 avoid miscounts due to polysomaty. The term polysomaty, originally defined by Langlet in 1927, refers to that oondition wherein one or more tissues of a diploid organism contain some cells of varying degrees of polyploidy. The presenoe of suoh endoploidy or poly- somaty in Atriplex was first reported by Witte (1947) in Atriplex Eatula and later by Stutz, et al. (1975) in Atriplex canescens. Although it is a concern when using mitotic root-tip smears, poly- somaty was observed in only three populations and, then, only in a minimal percentage of cells (see Fig. 14). As shown in Table 35, several species contain one or more levels of polyploidy. This is even in addition to the three distinct levels of ploidy between species as shown in Table 36 and Figs. 16 through 38. The only completely diploid species is!• welshii. Atriplex falcata and,!. cuneata ssp. introg;:essa a.re mostly diploid in nature, but one tetraploid population was found in each. Atriplex cuneata, typically a tetraploid species, has a distinctive diploid ecotype, located in the northeast corner of Utah. All!• corrpga.ta examined was strictly tetraploid. Atriplex ga.rdneri is largely tetraploid with a few diploids scattered along southern Wyoming. Atriplex tridentata, the only hexaploid species in the complex, contains at least one population that is tetraploid. As yet, only minimal karyotyping has been completed on any of the species of Atriplex. Most of the species in this complex appear to have chromosomes which range in size from 0.764 to 1.2735 microns and a.re metacentric; only one of these shows a 112 Fig. 14-15. Polysomaty in one root-tip of A. falcata from northwest of the Desert Moutains in Uta. 14. 2n:36 (endoploidy). X 4370. 15. 2n=18. X 7045• 113 TABLE 36. Cytological sUIIlilla.ryof chromosomal races in the !• s;a.rg.neri complex Chromosome number Species 2n•18 2n=36 2n•54 !• welshii X !• acanthoca.roa X X !• cuneata X X !• cuneata ssp. introgressa X X !• falcata X X !• gardneri X X !• obovata X X-- X !• col.'l."Uga,ta X !• tridentata X X 114 16 Fig. 16-19. Cytological microgaphs of chromosomes of!• falcata (2n=18). 16. 8 miles west Mdlake, Idaho. x 3880. 17.-12 miles south Grouse Creek, Utah. x 3730. 18. 7 miles west Ha, Alberta, Caada. x 3820. 19. Near Dolly Vaden, Nevada. x 3125. 115 21 Fig. 20-21. Cytological microgaphs of chromosomes of -A. welshii (2n=18). 20. 5·miles south Woodside, Uta. x 4300. 21. 5 miles south Cisco, Uta. x 5890. 116 .. 23 Fig. 22-24. Ctological micrographs of chomosomes of!• cuneata ssp. introgessa. 22. Tpical 2n=18, Wellington, Utah. x 3820. 23. 2n=27, 10 miles south Piee, Utah; probably a putative hbrid of!• cuneata ssp. introgessa ad!• cuneata. x 3560. 24. 2n=36, Cabon-Eery Co. Line on Hw U.S. 6-50, Utah. x 3100. 117 25 Fig. 25-26. Ctological micro.aphs of chromosomes of the diploid A. cueata (2n=18). 25. 3 miles south Bonaza, Uta. x 6600. -26. 16 miles south Bonaza, Uta. x 4780. 118 27 , 28 Fig. 27-28. Ctological microgaphs of chomosomes of the tetraploid !• cueata (2n=36). 27. 1 mile east Thompson, Utah. x 7040. 28. Shiprock, New Mexico. x 7670. 119 29 Fig. 29-30. Ctological microgaphs of chromosomes of A. corata '(2n�36). · 29. Thompson, Uta. x 5030.· 30. Wellingto;, Uta. ·x 5670. 120 31 32 Fig. 31-32. Ctological micrographs of chromosomes of A. gadneri (2n=36). 31. 10 miles south Lovell, vloming. x 7000.- 32. Rock Springs, Woming. x 6430. 121 Fig. 33-34. Ctological micrographs of chromosomes of the diploid A. gdneri (2n=18). 33. 27 miles east Rocksprings, Woming. x 4830. 34. 1 mile east Red Desert, Woming. x 4870. 122 •• 35 36 ' Fig. 35-38. Cytological microgaphs of chromosomes of A. tridentata (2n=54). 35. 13 miles west Hinckley, Uta. x 3670.- 36. South Patoun, Utah. x 4120. 37. 4 miles west Ehaim, Utah. x 3830. 3s. 1 mile south Wellington, Utah. x 3880. 123 secondary constriction, and the satellite is located 0.3 units from the centromere. One acrocentric chromosome has also been observed with consistant a.rm ratios of 1.0:0.63. As previously mentioned, the cytology of these subshrubs has become one or the most valuable tools in defining each species. When the cytological data is combined with the ecological and morphological measurements, the resolution of each species into distinct units becomes realistic. Thus, all evidence so far accumulated strongly indicates that the diploid species, 2n•18, are characterized by an upright habit, relatively fine-textured, linear leaves, and drop-like to burred fruits. They usually occur in rather small, isolated communities scattered. throughout the Intermountain West• .Additional diploid populations have been found in both!• ouneata and!• ga.rdneri, but these resemble more closely their putative tetraploids. The -A. cuneata diploid appears to be restricted primarily to the northeast corner of Utah and is characterized by having very large obovate to ovate leaves, both of which are atypical of the tetraploid. Also, several plants of !• cuneata north of Price, Utal\ were found to be diploid (Table 35). This suggests that the diploid form may be more widespread than originally thought. The!• gardneri diploids have been noted at three locations in southern Wyoming. One of these, located one mile east of Bed Desert, Wyoming, was studied extensively, .and no distinctive characteristics were observed which would separate it clearly from the typical tetraploid populations. As mentioned above, several polyploid forms are usually associated with the diploid populations; however, the tetraploids 124 occupy extensive areas, in contrast to the diploids which occur in small isolated pockets. Tetraploids generally have a low, compact habit with short, either narrow or rather broad leaves and moderately tuberculed fruits. Atriplex ga.rdneri, a typical tetra- ploid, occupies the widespread northern distribution of this complex. Although both diploids and tetraploids have been detected in!• gardneri, most sampled populations were tetraploid. Atriplex corrugata and typical!• cuneata are also vigorous tetraploids but restricted primarily to southeastern Utah and western Colorado. The diploid form of!• cuneata, as indicated previously, appears to be geographically- isolated from the tetraploid and morphologi- cally distinct in its leaf and habit characters. These two factors alone strongly suggest that taxonomic clarification is needed to separate them. The only hexaploid species, 2n=54 (excluding!• obovata which has diploid, tetraploid, and hexaploid populations), appears to be!• tridentata. This hexaploid is characterized by a habit of erect stems, linear to moderately- wide leaves, and typically smooth-sided fruits. It also appears to have a widespread distribution, occurring in scattered populations throughout most of Utah and neighboring states. Only one known population of !• tridentata is tetraploid, 15 miles south of Fish Springs, Utah. Both mitotic and meiotic chromosome counts showed this to be a tetraploid population. In conclusion, then, it appears that the evolutionary path of a certain species can be followed in some oases by comparing the 125 numerical relations of its chromosomes with those of other species within the genus. The essential genetic material is a major factor in determining evolutionary patterns. However, the chromosome number itself represents the number of packages into which this genetic material is divided. Not only can the rate of evolution be judged by these chromosome numbers (poly-ploids respond very slowly due to their duplicate chromosome complement as compared to diploids), but also phylogenetic patterns can be extrapolated, i.e., diploids gave rise to the poly-ploids. Nevertheless, all evidence so fa.r accumulated strongly suggests that the chromosome number is probably more constant than a;ny single morphological characteristic that is available for species identification in this complex. CHAPTERIV JOOOLOGICALAND:BIOGEOGRAPHICAL STUDIE.S Materials and Methods To study the ecological factors, observations were made on general distribution (latitude, altitude, characteristic soils, slope, and density} and associated species. Care was taken to determine the similarities and differences in habitat and environ- ment among the various populations and species. Herbarium specimens, fruits, and soil samples were taken from most populations. Voucher specimens are deposited in the Brigham Young University Herba.rium. Plant specimens and fruits were collected from an approximate 1/10 acre plot in the most homogeneous part of each population. Herbarium specimens were pressed in standard plant presses and stored for morphological analysis. These specimens were mainly from plants which were setting fruit, since the fruits are required for proper identification. In addition, fruits from individual plants were collected in small seed envelopes and bulk harvested in number 1O brown paper bags for germination and cytological studies. Soil samples were taken from the upper six inches of soil at three randomly selected sites within each homogeneous population and then pooled. Texture, pH, total soluble salts, and free carbonates were determined on each. Texture was analyzeq. by the 126 127 ~ometric method described by l3ouyoueos (1936, 1951). A l3eckma.n Glass Electrode pH Meter was used on 1:1 and 1:5 soil-water I ratios to determine the hydrogen ion concentration. The total of soluble salts was dete:z.,nined on saturated soil paste by the use of a :BeckmanElectrical Conductivity Bridge (Model RC 216B2). Free carbonates were determined by adding 10 percent hydrochloric acid to a small soil sample and then scoring the effervescence (rated from 1-4 with 1 representing no reaction and 4 representing a very vigorous effervescence). ResU.lts and Discussion Atriplex appears to thrive best on eroded slopes, blowout areas, and sparsely vegetated flats of relatively high salt concen- tration. Possibly the most inherent characteristic of the Atriplex environment is its harsh climate. The climate varies considerably over this vast area but appears to be consistent in having relatively hot s-ummerdays with cool nights and long, cold winters. Tempera- tures generally increase from January to July and August, which are the two hottest months, and then decrease. Moisture appears to increase from a low in the winter months to a high in May or early June; there seems to be a minimal amount of new moistu:re when temperatures are the warmest. Table 37 summarizes the environmental parameters of each species in the subshrub complex. Most species in this complex grow in relatively pure stands throughout the Intermountain West. For such extensive acreage, a minimumnumber of associated species have been observed. The types of flora most commonly associated with Atriplex are halopb;ytes a.nd TABLE37. Environmental parameters of each species in the Atriplex gardneri complex. Parameters Species Temperature range (~) Precipitation Salt tolerance J !• corrugata 5-15 84-100 5-10 12,500 4,000-6,000 Clay or silty loam !• cuneata 5-10 82-98 5.5-10.5 20,000 4,000-6,000 Clay or silty loam !• cuneata ssp. intro. 5-10 82-98 5.5-10.5 1,500 4,000-6,000 Clay to clay loam !• falcata 4-14 85-95 7-14 3,000 4,950-5,150 Mostly loam !• gardneri 2-11 84-94 7-11 26,000 5,110-7,400 Loam to clay !• tridentata -18-5 86-91 7-17 88,000 4,200-7,200 Clay or clay loam !• welshii -25 113-115 2.1-s.4* 1,600 4,000-6,000 Clay ..-.953-196, rainfall average was 5.97 inches. I\) co 129 xerophytes. In areas with high salt content, the· _pa.lophytic plants probably exist because 0£ their capacity to absorb water irrespec- tive of the high salt concentrations (Costing, 1956). Xerophytic plants, however, may not be able to endure physiological d:r!ought but can tolerate physical d:r!ought due to lack of rain or dr,y soil. The most commonplants associated with the species of the!• @sPeri complex are listed in Table 38. Distributions 0£ the four polyploid species of Atriplex included in this study a.re mapped in Fig. 39. As can be seen, the center of distribution for most of the species is the state of Utah and its adjacent areas. Most polyploid species, except - A. gp:dneri, are included in this area, i.e., !• eornga.ta, !• cuneata, and!• tridentata (see Figs. 40, 41, and 42). Atriplex ga;i;dneri occupies mostly the northern extremes of the complex•s distribution (see Fig. 43). The diploid,!• falcata, has populations soatt~ throughout the entire Intermounta.in West; whereas, the other two diploids,!• welshii and!• cuneata asp. introp;ressa, are restricted primarily to southern Utah (see Fig. 44). The Atriplex subshrubs a.re generally considered to be eon.;. fined to salty soils. Dayton (1931), for example, published, "Fewplants are more alkali-tolerant truµi these species." While it is true that most Atriplex species grow on soils that a.re normally too high in soluble salts for cultivated crops, this is not al~s the case. Gates, et al. (1956) found some of the subshrubs to be well adapted to soils of high salt and sodium content, but not limited to areas high in these components. They found!• nuttallii (most likely!• tridentata) to be ur.ireliable as 1;0 TABLE;a. A species list of' plaitts associated with the Atriplex B¥4Beri oemplex Scienti£io name Commonname Agrop:yron trachyeaulum Slender wheatg:t"aSs illenrolf'ea occidentalis Pickleweed A.rtemisia tridentata Big sagebrush Bouteloua s;acilis Blue gra.ma. grass Eriogonum infiatum Umbrella plant {Bladder weed) Ceratoides lanata Winterf'a.t Balos,ton glomeratus Ha.l.ogeton X:oehia scoparia Fireweed Lepidium densifiorwn Prairie pepperweed Opuntia polya,cantha. Prickly pear cactus QrYzopsis h.ymenoides Indian ricegra.ss Salsela ka.ll Russian thistle ------Sarcobatus vermiculatus Greasewood Sita.n.ion hystrix Squirreltail grass Stipa. co;mata Needle and thread grass Sueada depressa Parsh seepweed 131 Fig. 39. The approximate geographic distribution of polyploid species in the!.• gardneri complex. 132 ••• •• • .... ••...... r.:: .. ••••••••••••• . .. A. gardneri . ······ : . ········•······•: .. ;,•... ..· ••··••: :·•···· ················ .... ·•••·I ··········· I• • f A, trid~tata • \. !···················· ...... -., ' ; r-;•-.~---...···· ...... ~.-f-A. cuneata j • r-··•: ,•i·I••·····. : ··..] ...... ;...... f - ...... ••,············· ...-: I , .....( ...... ·• .. . . . :· ...... , .. : ..: ·.... · ..• ... 133 Fig. 40. Distribution map of!• co;:rugata; the circles mark populations that were studied both cytologically and morphologically, the solid circles those that were analyzed only morphologically. --'134 • Rock Sprl1191 • Salt Lake City • •• • •Grand Junction 135 Fig. 41. Distribution map of A. cuneata. The circles mark populations that were studied both cytologically and morphologically, the solid circles those that were analyzed only morphologically. 1, 2D1=27and 36; 2, 2n;:18, 27, and 36; 3 and 4, 2n;:18. 136 •Pocatello • Rock Springs •Salt Lake City • 0 • • Grand Junction 0 • 0• 0 _., VI -.J Fig. 42. Distribution map of A• tridentata. · The circles are populations that were a.nalyzed both cytologically and morphologically.and the solid circles thase that were analyzed only morpho- ·· logically. The single arrow marks the tetraploid population. 138 • .,,_g C: ... C: u :, C)...... :.,,·~ ... 0. 0111 1111. 0 ' • .M• .....u ,.. • :vt•~• 00 ') o • 0 • ~- 0 • 0 • 0 c-• • 0 •-o. • •• 0 t 0 139 Fig. 43 •. Distribution map of A• gardneri. · The triangles indicate populations that were analyzed cytologically and morpho- logically and the circles those that were analyzed only morphologically. The three arrows (1, 2, and 3) mark the diploid collections. 140 • • • • • A 4. • 4 • Butte •A A • • Pocatello .A•• • t> • • • A A • • • ,3 A •Cheyenne •Salt lake City 141 Fig. 44. Distribution map of the diploid species,.!• falcata, !• welshii, and!• cuneata ssp. intro,sressa, with representative symbols as follows: !• falcata 0 Studied cytologically and morphologically. • Studied morphologically only. !• welshii a Studied cytologically and morphologically •. !• cuneata ssp. introgressa A Studied cytologically and morphologically. 1, A. cuneata ssp. intro,sressa 2n=36; 2, !• cuneata ssp. intro- gressa 2n=18 and 27; 3, !• falcata 2n=36. 142 0 0 •Pocatello o• 0 •o • • 0• ••·~ • 0 0 eoeo 143 an indicator of specific soil characteristics because of its wide range in adaptibility. Vosler (1962) found!• nuttallii (probably !• gardneri) growing on eight different soil textural classes in the l3ig Horn :Ba.sin of Wyoming• .Although fine-textured clay soils are thought of as characteristic of these plants, he reported that the majority of sites studied were characterized by loamy soils. Nevertheless, it appears that, for the most part, the subshrubs typically occupy the desert soils which range in color from ashy gray to a light buff or reddish brown. As shown in Table 39, the textural analysis of the entire complex shows considerable variation, ranging in sand from 8 to 72 percent, in clay from 6 to 60 percent, and in silt from 6 to 74 percent. All species and their populations appear to grow in soils relatively high in fines, from 42 to 92 percent, with the exception of!• gardneri; some populations of!• gardneri grow on soils containing as little as 18 percent fines. Atriplex coz:rugata, !• cuneata, and!• gardneri are primarily restricted to soils class- ified as loams or clays;!• tridentata and!• welshii grow on the heavier soils (clay to clay loams); and!• falcata occupies the better loamy soils (see Table 40). Gates, et al. (1956) suggest that salinity is the most important limiting soil factor in the distribution of Atriplex. They conclude that all species have an upper level of salinity tolerance and that when several species of Atriplex are sympatric, each usually occupies a site of different salinity. In view of the analysis shown in Table 39, such a statement is difficult to support. It is obvious, however, tha.t other soil characteristics T.A.13LE39. Soil analysis of soils occupied by the subshrubs of the genus Atriplex ..i::,..... pH % % % % Soil Salt content Free Source type (ppm) sand silt cley fines 1 :1 1:5 Difference carbonate* !• corrugata silty Wellington, Utah 20 60 20 80 loam 2,990 a.os a.20 .15 4 Green River, Utah 12 28 60 88 clay 12,221 a.30 3.90 .60 4 silty Cisco, Utah 10 42 48 90 clay 748 8.30 a.85 .55 4 clay Price, Utah 24 44 32 76 loam 1,185 8.65 9.60 .95 4 sandy East Thompson, Utah 56 30 14 44 loam 244 8.10 8.40 .30 3 Carbon-Emery County 66 clay Line, Utah 34 30 36 loam 6,321 8.50 a.60 .10 4 s:i,lty Thompson, Utah 18 68 14 82 loam 3,~00_ 8 •.to a.10 .oo 4 !• cuneata cley Price, Utah 34 38 28 66 loam 4,248 7.95 a.30 .35 4 Thompson, Utah (2) 22 18 60 78 clay 327 8.35 a.80 .45 2 silty Thompson, Utah (1) 18 68 14 82 loam 3,900 8.10 a.10 .oo 4 Ea.st Thompson, silty Utah (2) 18 74 8 82 loam 2,704 7.95 8.10 .15 4 Ea.st Thompson, sandy Utah (1) 56 30 14 44 loam 244 8.10 a.40 .30 3 silty Cisco, Utah 30 62 8 70 loam 1,054 . 7.65 7.90 .25 4 si}ty Tuba City, Arizona 24 68 8 76 20,558 a ..60 a.70 .10 3 loam .> !• falcata silty Grouse Creek, Utah 18 65 17 82 loam 1,116 a.35 a. 10 .35 4 Austin, Nevada 36 42 22 64 loam 645 a.45 a.75 .30 4 Wells, Nevada 34 42 24 66 loam 237 e.25 e.15 .50 4 Lone Pine, Idaho 50 28 22 50 loam 2,995 e.10 e.25 .15 3 clay Mud Lake, Idaho 40 30 30 60 loam 540 a.oo 8.50 .50 4 Jericho, Utah 42 38 20 58 loam 438 a.50 a.95 .45 4 Desert Mt. , Utah ( 1) 38 40 22 62 loam 438 a.60 9.10 .so 4 Desert Mt., Utah (2) 36 42 22 62 loam 625 a.oo a.40 .40 4 Woodruff, Utah 18 30 32 82 clay 760 8.oo e.40 .40 4 !• mdneri ..A, clay \JI Bridger, Montana 22 40 38 78 loam 1,813 8.ao 9.40 .60 2 ...... i:=,. TABLE39. Continued 0\ pH Soil Salt content Free Source % % % % sand silt clay .fines type (ppm) 1 :1 1:5 Difference carbonate* silty Manila, Utah 16 44 40 84 clay 2,184 8.05 a.30 .25 4 sandy Ea.st Manila, Utah 82 6 12 18 loam 324 1.80 8.20 .40 4 !• P.'8.'t'dneri sandy Rock Springs, Wyoming 72 14 14 28 loam 150 8.30 8.70 .40 3 Ea.st Rock Springs, sandy Wyoming 68 16 16 32 loam 139 8.45 8.85 .40 4 silty Fort Bridger, Wyoming 36 56 6 62 loam 26,672 7.30 1.10 .40 4 sandy Lyman, Wyoming 48 22 30 52 clay 957 8.50 a.90 .40 4 loam clay Wamsutter, Wyoming 42 24 34 58 loam 568 7.95 8.15 .20 2 Rawlins, Wyoming 26 14 60 74 clay 585 8.75 9.25 .50 4 clay Lovell, Wyoming 34 28 38 66 loam 1,757 8.25 8.45 .20 3 Casper, Wyoming 16 34 50 84 clay 512 8.30 8.85 .50 1 clay Saco, Montana 34 30 36 66 loam 1,058 7.30 7.75 .45 1 Shelby, Montana 54 38 18 56 loam 440 8.oo 8.35 .35 3 !• nu.ttallii Canada-U.S.A. Border (Hwy15) 16 28 56 84 clay 3,311 8.20 a.50 .30 1 Ferry, Alberta, 18 loam Canada 42 40 58 367 a.35 a.as .50 4 North Ferry, Alberta, sandy Canada 48 46 6 52 loam 2,139 8.15 a.15 .oo 1 North Ferry, Alberta, clay Canada (2) 26 32 42 74 5,802 a.15 a.30 .15 1 !• obovata North Shiprock, New clay Y.1exico 40 30 30 60 loam 946 a.25 a.10 .45 3 West Shiprock, New clay Mexico 14 36 50 86 3,213 1.ao 8.10 .30 4 sandy Dinnehotso, Arizona 58 18 24. 42 clay 2,277 8.60 9.20 .60 4 loam silty Tuba City, Arizona 24 68 8 76 loam 20,558 8.60 8.70 .10 3 !• tridentata clay Austin, Nevada 28 44 28 72 loam 39,602 8.35 8.a5 .50 4 silty Lund, Utah 30 62 8 70 1,426 8.35 a.6o .25 4 loam -.:i TABLE39. Continued .j:l,..... 0) pH % % % % Soil Salt content Free Source type sand silt clay fines (ppm) 1 : 1 1 :5 Difference carbonate* Jct, Hwy 6-50 and silty 62 8 259 30 10 loam Hinckley, Utah 30 20 50 10 clay 1,717 8.50 8.55 .50 4 clay Grantsville, Utah 26 44 30 74 loam 1,931 8.65 9.35 .10 4 .!• tridentata sandy Rock Springs, Wyoming 58 28 14 42 loam 43,621 8.45 8.80 .35 4 silty Wellington, Utah 8 50 42 92 clay 31,806 8.85 9.00 .15 4 Carbon-Emery County clay Line, Utah, Hwy 34 30 36 66 loam 6,321 8.50 8.60 .10 4 6-50 silty Ephraim, Utah (2) 14 42 44 86 clay 605 8.50 8.9o .40 4 . Ephraim, Utah ( 1) 12 40 48 88 clay 3,578 8.45 8.90 .45 4 Salina, Utah 22 29 49 78 clay 7,756 8.30 8.80 .50 4 Sigurd, Utah 22 33 45 78 clay 26,950 9.40 9.65 .25 4 Painter Spring Road, 12 16 88 silty Utah 72 loam 87,131 8.30 8.65 .35 4 cuneata __ intragyessa ------~-· !• rum. Wellington, Utah (1) 24 30 46 76 clay 1,414 7.60 7.95 .35 4 silty Wellington, Utah (2) 24 66 10 76 loam 1,374 1.65 7.95 .30 4 10 miles south Price, clay Utah 24 44 32 76 loam 1,185 a.65 9.60 .95 4 Carbon-&nery County clay Line, Utah, Hwy 34 30 36 66 loam 6,321 a.50 s.60 .10 4 6-50 !• welshii Cisco, Utah (1) 16 36 48 84 clay 1,550 1.15 a.oo .25 4 Cisco, Utah (2) 14 36 50 86 clay 1,386 1.10 a.10 .40 4 *Free carbonate reaction with 1eyfoHCL. Rated from 1-4 with 1 representing no reaction and 4 representing a very vigorous effervescence. _,. \.0 TABLE40. Summary of the soil analysis of soils occupied by the subshrubs of the genus !triplex (condensed from Table 39) Soluble Species ,% % % % Soil type pH Free carbonate* sand· silt ClaJF .f,i.nes salt - !• corrugata 10-56 28-68 14-60 44-90 Loam to clay 244-12,221 8.05-8.65 High !• cuneata 18-56 18-74 8-60 44-82 Loam to clay 244-20,558 7.65-8.60 Relatively high !• cuneata ssp. 24 30-66 10-46 76 Clay and 1, 185-1,414 7.60-a.65 Relatively high introgressa. clay loam !• falcata 18-50 28-65 17-52 50-82 Mostly loam 438-2,995 8.00-8.60 High !• gardneri 16-82 6-56 6-60 18-84 Loam to clay 139-26,672 7.30-8.80 Rel. moderate !,. obovata 14-58 18-68 8-50 42-86 Loam to clay 946-20,558 1.ao-8.60 Relatively high Clay and !,. tridentata 8-58 20-72 8-50 42-92 clay loam 605-87, 131 7.00..;.9.40 Vecy high !• welshii 16-34 30-66 10-50 66-86 Clay and 1, 185-6, 321 7.60-a.50 Vecy high clay loam *Free carbonate reaction with 10"/4HCL. Bated from 1-4 with 1 representing no reaction and 4 representing a very vigorous effervescence. \JI.... 0 151 suoh as texture and carbonate content are equally important. The concentration of soluble salts also shows a wide range of variation, from 139 to 87,150 ppm salt. Atriplex falcata appears to be the only species which prefers non-saline soils. Atriplex tridentata, restricted basically to cl~ and cl~ loam soils, shows the most salt tolerance, exceeding 87,000 ppm. Atriplex corrugata, !.• cuneata and!• ga.rdneri are only moderately tolerant of salt. As shown in Tables 39 and 40, the pH values show consider- able variation among the seven species, but all soils appear to be somewhat basic, ranging from pH 7.5 to e.5. This corroborates the reports of Hanson (1962) and Vosler (1962), although the range is less than that reported by Hanson, i.e., pH 8.2 to 10.3. Such high pH values usually indicate the presence of carbonates of calcium and magnesium (Richards, 1947). :Because most of these soils were high in free calcium carbonate, active effervescence ratings were observed when treated with 10 percent hydrochloric acid (see Tables 39 and 40). The only soils regarded as low in calcium carbonate are those occupied by populations in Canada which were excluded from this study. The foregoing data on soil pH substantiates the evidence presented by Flowers (1934) and Gates, et al. (1955) that pH values bear little significance by themselves# Nevertheless, when the moisture content of a sample of soil which is rich in sodium carbonate is changed from a low to a higher level, the pH shows a corresponding increase. Using this as a.n indicator, soils that contain relatively high quantities of free sodium ca.n be easily detected. Most of the species have at 152 least some populations growing in soils which are relatively high in sodium content. Richards (1947) suggests tha.t any pH change over plus 0.4 is indicative of high sodium soils. As shown in Table 39 and as e:rpected, most .A.triplex species occupy soils fairly high in sodium. A cluster analysis of the population parameters recorded in Table 39 shows the soil characters to be highly diverse (Fig. 45). However, when this data was scored, by species, into classes for each parameter and then clustered using these "class means," particular patterns became quite apparent (see Tables 41 and 42). The environmental parameters of!• tridentata and!• cor:t"UA'ata clustered together with a similarity index of 90 percent (see Fig. 46). Thus, both species appear to favor the heavier soils which are high in salt and sodium content. This was also folllld to be true by Esplin, et al. (1937) and Windle (1960) for!• tridentata and West and Ibrahim {1968) for A•corr,Jgata • .Atriplex cuneata and the northern .Atriplex, designated as!• nuttallii in this analysis, seem to be in the moderate range in most soil characters;!• falcata shows a low tolerance for both heavier soils and high salt and sodium concentrations (see Figs. 47, 48, and 49). Although !• welshii and!• cuneata sap. introp:essa occupy the heavier cl~ soils, they still appear to have a low tolerance for salinity. In S'1lDIIJl8rY,the soil analyses show some significant eda.phic differences between soils occupied by the various species, but no species appears to be restricted in distribution by a narrow tolerance range for any speci.t'ic soil factor, except!• falcata, which appears to occur chief'ly in benchland areas on coarse-textured VI.... \)4 Fig. 45. Cluster analysis of 63 populations of Atriplex according to their environmental parameters (data analyzed is recorded in Table 39). Population identification is as follows: 1-7, !• corrugata; 8-14, !• cuneata; 15-23, !• falcata; 24-40, !• ga.rdneri; 41-44, !.• obovata; 45-57, !• tridentata; 58-61, !• cuneata ssp. introgressa; 62-63, !• welshii. POPULATION 41 60 13 46 58 59 48 49 39 43 18 42 7 8 52 40 16 53 31 34 23 21 38 5 17 27 45 14 47 29 2 30 4 15 35 62 63 33 24 25 II I 37 54 JO 6 61 55 22 J9 32 3 20 36 9 12 26 28 SO 44 51 56 57 lJ L{J 1 J - 'J 1rJIJ 1 lJ 90, . IJL.. l - 80, ½- -- I L_ 70 -- ' 60, t_ l: ---- .i: J! ·-E so ·-.. 40 30 --- 20 JO VI TABLE 41. Class rating of soil obaracteristios as recorded in Table 39 (see Table 42 tor calculated means) pH Class % % % % Texture Soluble salt Free ratings sand silt clay fines carbonate* 1 : 1 1:5 Difference 1 0-10 0-10 0-10 0-10 Clay 0-300 7 .0-1.3 1.1-1.9 0-.2 1 2 11-20 11-20 11-20 11-20 Silty clay 300-600 1.3-1.6 7.9-e.1 .2-.4 2 3 21-30 21-30 21-30 21-30 Clay loam 600-900 1.6-1.9 a.1-0. 3 .4-.6 3 4 31-40 31-40 31-40 31-40 Silty loam 900-1,200 7.9-8.2 s.3-s.5 .6-.e 4 5 41-50 41-50 41-50 41-50 Loam 1,200-1,500 e.2-a.5 8.5-8.7 .a ..1.0 • • • Sandy clay 6 51-60 51-60 51-60 51-60 loam 1,500-2,000 a.5-e.a a.1-s.9 • • • • • • 1 61-70 61-70 61-70 G1-70 Sandy loam 2,000-5,000 8.8-9.1 8.9-9.1 • • • • • • 8 71-80 71-80 71-80 71-80 Sand J,000-15,000 9.1-9.4 9.1-9.3 • • • • • • 9 81-90 81-90 81-90 81-90 • • • 20,000+ 9.4-9.7 9.3-9.5 • • • • • • 10 91-100 91-100 91-100 91-100 • • • • • • 9.1-10.0 9.5-9.7 • • • • • • *li'ree carbonate reaction with 10% HCL. Rated from 1-4 with 1 representing no reaction and 4 representing a very vigorous effervescence. VI... VI TABLE 42. Calculated parameter means for each species from data recorded in Table 39; means were com- puted according to the class ratings in Table 41_ - Class rating means pH % % % % Texture !:loluble Free Species sand silt clay fines salt 1 :1 1:5 Difference carbonate* !• corrugata 3.14 3.86 5.00 8.14 3.43 5.43 4.86 5.29 2.29 3.86 !• cuneata 3.43 2.43 5.57 7.71 3.86 5.29 4.29 4.00 1.11 3.43 !• falcata 4.10 3.30 4.60 7.10 4.30 2.90 4.ao 5.60 2.60 3.90 !• gardneri 4.67 3.75 3.33 6.17 3.92 3.83 4.50 4.a3 2.83 2.92 A• nuttallii 4.20 3.20 4.20 1.00 3.80 5.20 4.40 4.40 1.80 2.00 !• tridentata 3.15 3.69 5.08 8.08 2.77 7.46 5.46 6.23 2.38 4.00 A• welshii 2.03 4.33 4.67 0.17 2.17 5.50 4.00 3.83 2.50 4.00 *Free carbonate reaction with 100/4IICL. Rated from 1-4 with 1 representing no reaction and 4 representing a very vigorous effervescence...... VI 0\ 157 POPULATION .... A. A. A...... tridentata corrueatG obovata -Ishii ....cuneata ....nuttallii falcata ...9ardneri 7 1 6 8 2 s 3 4 JOO 95 90 85 I 80 I 75 Fig. 46. Cluster analysis of the Atriplex species according to their edaphic factors (clustered according to the calculated means in Table 42). 158 • TEXTURE 0 SOLUILI SALTS 10 high 0 0 • • • 0 clay • 7 6 8 2 5 4 3 A. A. A. A. A. A. A, A. tridentata corrugata obouata -Ishii cuneata nuttallii 9ardneri falcata SPECIES Fig. 47. Ed.aphic paramete~s graphed against the species order from the cluster analysis program (see Fig. 46). 159 s.o A. 9arclneri O A. nuttallii 0 A. falcata 4.0 0 A. obovata Q z C "' Oo A. corrugata 3.0 I I I I 7.0 FINES Fig. 48. Ranking of species by percent sand and percent fines. Data taken from the calculated parameter means recorded in Table 42. (!. falcata also includes the diploid populations of !• welshii and!• cuneata ssp. introgressa.) 160 5.S 5,0 • A.. obovata (6) • A.. falcata (3) PH 1:1 -t.S A. nuttollii • (S) A. cuneata • {2) 4.0 3.5,._ __ ...,. ______. s.o 6.0 7,0 PH 1:5 Fig. 49. Ranking of species by relative sodium concentra- tions as indicated by pH dilution series from calculated means (see Table 42 for actual pH values). 161 soils with relatively low salt content. Overlap of each soil fac- tor measured was found under almost all species studied. Within certain ranges for each edaphic factor, all seven species appeared to be well adapted. Consequently, mixtures of species might be expected in areas where these edaphio characteristics overlap. However, this is seldom the case; almost all of the species occur in pure stands. Therefore, either some other factor or factors which were not measured by this study mu.st have limited·plant growth to the single species occupying the area, or each species ma.y be composed of various ecotypes, each with its own tolerance range. F.cotypic variation within a species, as described above, might be responsible for the wide variability within soils occupied by the same species. Thus, most populations appear to be· genetically adapted to tolerate certain maximumor minimum limits in their environment1:;1. Whenthese limits are exceeded, populations no longer survive, or new plants of similar genetic adaptation fail to become established. However, since plant populations and species are composed of variable individuals, constantly inter- breeding, new genetic combinations most likely occur which are adapted to tolerate limits different from those of their parents. Such new combinati.ons may serve as the basis for the establishment of ecotypes within species with quite different physiological ranges of tolerance from the original species. Through inter- breeding and natural selection over a period of time, various ecotypes with different tolerance ranges for various edaphic factors ma.y have developed within the species. Morphologically 1~ these populations might not be distinguishable, although earlier analysis suggests otherwise. If such ecotypio variation is present for the wide adaptation within each species, then the reliability of the use of species as a soil indicator is considerably reduced. PHENOLOGICALSTUDIES In these studies of the!• ga.rdneri complex, it became necessary to germinate the seeds collected in the field. Germinants were needed for the establishment of nursery seedlings and for the harvesting of root-tips for cytological purposes. After ma.:ny attempts at germinating the seeds by using paper dolls, soil plantings, petri dishes, and germination chambers, it became obvious that the seeds ge:rminated poorly when encased by their bracts. Simi- lar problems were encountered in other Atriplex species by Beadle (1952) a.nd, just recently, by La.ilha.oar-Kind and Laude (1975). Materials and Methods The fruit of Atriplex, classified as an utricle, is generally encased in thickened upper leaves or fruiting bracts which are often sculptured with tubercules. Both bra.cted encased seeds and excised seeds were analyzed for ge:rminability, seed fill, and seed viability. Each species and the number of sources from which fruiting bracts were collected and analyzed are recorded in Table 43. For seed germination studies, seeds were planted in flats filled with steam-sterilized soil, in dampened paper dolls, and in disposable plastic p~tri dishes on moistened germination pads. The first external evidence of germination of the seed occurs when the 163 164 TABLE43. Species list and number of sources included in the germination studies Maximumnumber of Species sources analyzed Atriplex corrugata s. Wats. 22 Atriplex cuneata A. Nelson 26 Atriplex cuneata. ssp. introgressa Hanson 15 Atriplex falcata (M. E. Jones) Standley 18 Atriplex gardneri (Moq.) Standley 22 Atriplex nuttallii Watson 10 Atriplex obovata Hoq. 33 Atriplex tridentata Kuntze 69 Atriplex welshii Hanson 9 165 rad.icle emerges through the orifice at the apex of the bracts. As defined by Lawrence, et al. (1947), germination is "the development of plantlets from the seed." Thus, for a seed to be classified as germinated, its roots and epicotyl must have emerged from the seed coat. For this study, however, a seed was considered germinated when the radicle had pushed out of the bracts and when this root-tip had developed root hairs. The number of germinants were recorded on alternate days and then were either discarded or the root-tips were saved and processed for cytological analysis. Seedlings that germinated in soil were retained and trans- planted into commongardens for :further phenological studies. Since the germination of the seeds encased in their fruiting bracts was so low, several of the following treatments were tried to increase the germination percentage: 1. Fruits were exposed to various temperature treatments including freezing and thawing and prolonged cold. Fruits were given the following treatments for 45 and 234 days just prior to germination: (a) storage at room temperature {control); (b) washing 18 hours with water and followed by storage at room temperature; (c) storage at 4°c; (d) storage at -4°C; (e) storage at 4°c in alternating wet and dry conditions. Some samples of fruits were also frozen for seven months before germination. 2. X-ray photographs were used to identify filled seeds. Fruiting bracts were placed on clear plastic sheets and x-rayed for 1. 5 minntes at 5 milliamperes and 15 kilovolts by a Picker Portable X-ray Ma.chine ( the x-ray source was 23.5 inches above the film 166 plate). The x-ray film (Kodak MZ Industrex) was developed and the resulting ~hotographs were scored for seed fill by observations of the presence or absence of a seed encased in the bracts. Filled bractswerethen selected for use ill further germiIJa.tion studies. 3. Flotation on ethanol was used to select filled fruiting bracts £or germination. Fruits were noated in 95 percent ethyl alcohol. For the most pa.rt, only empty bracts noated; the heavier filled seeds settled to the bottom. Samples in which a relatively high percentage 0£ empty bracts were recovered from the bottom of the flask were a.gain noated in 75 percent ethanol. 4. Seeds were removed from the fruiting bracts and pericarp. They were excised by removing the bracts with an E:xa.cto knife and then germiIJa.ted on moistened germillation pads in petri dishes. :Because of the low germination percentages, it was necessary to test for viability 0£ the filled !raits. An oxidation-reduction indicator, 2,3,4 triphen;rl tetrazolium chloride, was used to test £or active respiration in the seeds. Only after the fruiting bracts were removed and the seed coat damaged was the tetrazolium salt able to gain access to the respiring tissue and give a positive test. Also, beoa.use germiIJa.tion percentages were so low, germi- Da.tion inhibitor studies were conducted to test tlie effect of the water-soluble extracts from the fruiting bracts on excised Atriplex, radish (Cherry Belle variety), and lettuce (Salad Bow:!.variety) seeds. M.eal prepared by grinding up whole fruits of selected species of Atriplex was soaked in five times its weight of water for 24 hours. The mixture was then filtered through cheese cloth and 167 centrifuged at 5000 times gra.vi ty (5000xG) for 10 minutes. Leachate thus obtained was used either in full strength or diluted in a series of 1:3, 1:5, and 1:10 leachate to water. Filled fruits selected by x-ray- photography, as described above, were excised and placed on germination pads in petri dishes and then watered with the serial dilutions of the leachate extract. Seeds in dishes watered with distilled water were used as controls. Those seeds which pushed out a radicle but failed to form root hairs were recorded as emergents and, as noted above, those which formed root hairs on emergent radicles were considered to be fully competent germinants. Seedlings germinated in white sand were also observed and their progress noted. In this study, 20 excised and pricked seeds were started together with 80 non-excised fruits. The populations included in this phenological study are recorded in Table 44. Results and Discussion The results shown in Table 45 indicate that the various temperature treatments had little positive effect on the germi- nability of the seeds. In fact, cold treatment reduced the germination in!• cuneata from Price, Utah. It appears that either the seed source origin or possible field preconditioning of these sources is important. Atriplex cuneata from east of Thompson, Utah, failed to germinate, whereas, the other three populations of!• cuneata yielded at least some germinants. Prolonged vernalization pretreatment of seeds exhibited little effect in enhancing germination (Table 46). Lehrer and Tisdale (1956) made similar observations in the germination of 168 TABLE44. Populations included in the phenological study of seed- ling development(* indicates those populations which failed to germinate any seedlings). Species Location Ji. corrugata *5 miles south Ferrin, Utah ~north of Woodside, Utah *5 miles east Green River, Utah Ji• cuneata 5 miles east Thompson, Utah *1.5 miles northeast Moab, Utah *5 miles south Emery, Utah 4 miles south Galahad, Alberta, Canada Ji• cuneata ssp. introgressa *1 mile south Wellington, Utah !• falcata 1.5 miles west Utah-Wyoming Border on Hwy 16 -l *15 miles south Wells, Nevada *12 miles south Montello, Nevada *Desert Mountains, Utah !• gardneri Laramie, Wyoming 4 miles south Manderson, Wyoming 50 miles north Casper, Wyoming Circle, Montana 10 miles east Hinsdale, Montana *15 miles north Manila, Utah *9 miles south Bridger, Montana 169 TABLE44• Continued Species Location !• gardneri iE-20miles south Lovell, Wyoming *1 mile east Rock Springs, Wyoming *3 miles east Glendive, Montana !• obova.ta 5 miles east Shiprock, New Mexico Mexican :Border 1 mile east Winslow, Arizona 10 miles sou.th Deming, New Mexico Palomos, Mexico !• tridentata 4 miles west fu):>hraim,Utah 1.5 miles south Sigurd, Utah 5 miles south Wendover, Utah *4 miles west Hinckley, Utah *1 mile north Grantsville, Utah !• welshii *5 miles south Cisco, Utah 170 TABLE45. Seed germination in four species of Atriplex: !• cuneata !• corrus;a.ta, !• falcata, and!• tridentata; each treatment entry represents 400 seeds. Treatments* Germination Species Source A B C D # !• cuneata Ea.st of Thompson, Utah 0 0 0 0 0/1600 o.oo South of Thompson, Utah 0 0 0 2 2/1600 0.12 Price, Utah 18 4 9 9 40/1600 2.50 Hanksville, Utah 0 1 O 5 6/1600 0.38 !• corruga.ta Thompson, Utah 0 0 0 0 0/1600 o.oo Blue Hountain, Colorado 0 0 0 1 1/1600 0.06 !• falcata Desert I•:ountains, Utah 1 4 3 1 9/1600 0.56 !• tridentata Wellington, Utah 4 3 2 6 15/1600 0.94 -lE-Treatments: A. Seeds stored at room temperature since collection. B. Seeds stored at 4°c for 45 days just prior to germination. C. Seeds stored at -4°C for 45 days just prior to germination. D. Seeds soaked for four hou:rs, washed, and then stored at -4°C for 15 days (repeated three times). 171 f'rui ts of' Nuttall' s Sal tbush in Wyoming. In contrast to both this data a.nd that of' Lehrer and Tisdale is that reported by McLean (1953). He suggested that!• nu.ttallii (Saskatchewan, Camda) has a dormant or rest period which can be broken by chilliIJg. Fruits that had been chilled had an average germiDation of about 20 percent, while unchilled .traits germina.ted only about 4 percent. PrewashiIJg for 18 houi-s, as well as soaking, freezing, and dz-ying, repeated several times, did induce some gem:i.Da.tion in!,. acanthoca:rpa, as did just just wa.shillg. This suggests the possible presence of' a water soluble il:lhibitor. (Chemical inhibitors, in relation to seed germination, will be discussed below.) The low germination percentage was thought to be a result of' either sparse seed fill or diminished seed viability. When the fruits were analyzed, the seed fill ranged from 0.5 to 29.5 percent, and the seed viability of' all sources was greater than 50 percent (see Table 47). The low gem:i.Da.tion or two sources, !• cuneata from Thompson, Utah, a.nd !• tridentata from Wellington, Utah, can be partially accounted for by both low seed fill and low viability; whereas, the other soui-ces appear to exhibit some sort of' dormancy, quiescence, or il:lhibition. One of' the most extensive studies of' Atriplex fruit germi- nation was carried on in Australia over a period of' many-years by Beadle (1952). He reported that germination of five species of' Atriplex was very low unless some treatment was applied to the seed coat. Germina.tion was apparently inhibited by high concentrations of' chloride ions in the seed coat. After removal of' some of the chloride ions by soaking the fruits in water for a period of' time, 172 TABLE46. Effects of washing and cold treatment on the germination of three species of Atriplex. Ea.ch treatment entry represents 100 fruits Treatments* Germination Species Source A B C D E # % !• acanthocarpa Delicias, Mexico 0 3 0 0 3 6/500 1.20 !• welshii Cisco, Utah 0 0 0 0 0 0/500 o.oo !• cunea.ta. Thompson, Utah 0 0 0 0 1 1/500 0.20 71-Treatments: A. Stored at room tempera.tu.re. B. Washed for 18 hours with water and then stored at room tempera- ture for 234 days just prior to germination. c. Stored a.t 4°c for 234 days just prior to germination. D. Stored at -4°C for 234 days just prior to germination. E. Stored at 4°c for 234 days in wet, dry wet, etc. cycles just prior to germination. 173 TABLE47. Analysis of the seeds in the germination experiment in Table 45. Filled fruits* Viable seeds** Species Source # % # % !• cuneata F.ast of Thompson, Utah 8/1600 0.50 4/8 50.0 (' South of Thompson, Utah 52/1600 3.25 43/52 82.7 Price, Utah 392/1600 24.50 308/392 78.6 Hanksville, Utah 460/1600 28.75 280/460 60.9 !• co:r:rup:ata Thompson, Utah 472/1600 29.50 368/472 78.0 Blue ¥10untain, Colorado 456/1600 28.50 288/456 63.2 !• falcata Desert Mountains, Utah 132/1600 8.25 123/132 93.5 !• tridentata Wellington, ·utah 20/1600 1.25 16/20 so.a *Percent filled fruits was determined by cutting open the fruit bracts • ..,..Percent viable seeds was determined by staining with tetrazolium chloride. I 174 a relatively high germination percentage was obtained. Stout and Tolman (1940) suggested that two to ten hours soaking was ample to remove a:ny water soluble inhibitor present in the varieties of sugar beet seeds with which they worked, and longer soaking had no influence upon germination. If this were true for species in the!• fi8:E1neri complex, then the germination data in Tables 45 and 46 should be mu.chhigher, unless another type of inhibitor is present, or else 18 hours is not sufficient washing time to remove all of the inhibitor. :Beadle (1952) found that two of the five species of Australian Atriplex had hard seeds with sufficient mechanical resistance to prevent germination, even after the water soluble inhibitor had been washed ou~ of the seed covers. His study suggests that the water soluble inhibitor may not ee the major factor in preventing germination, but that the hardness of the bracteoles is responsible. Simila;:r results were noted in fruits of !• welshi,! from Cisco, Utah. After the fruits were leached for 24 hours in running water and then soaked for 12 hours, they were blotted dry and set out on germination pads. A few samples were then sacrificed and excised each day to check the progress of germination. Especially in those fruits with large seed locules, the seeds began to germinate but were stopped by the mechanical structure of the bracts. The radicle would oftentimes elongate 5 to 7 mmbefore encountering structural resistance. Vest (1952) found this to be the case with!• confertifolJ.!. After the water soluble inhibitor was leached from the bracteoles. they remained mechanically resistant to germination due to the hard tissue of the bracteoles TABLE48. Germination of the suffrutescent shrubs in the genus Atriplex Germi.nants Fruits in bracts Fruits excised Fruits excised from bracts from bracts and radicle end pricked Number % Number " Number % A. acanthocarpa 26/2,044 1.27 9/12 75.00 30/39 76.92 A. currugata 2/10,300 0.02 6/62 9.68 118/186 63.44 A. cuneata 71/11, 930 0.56 ...... 61/70 87.14 A. ~• .ssp. intro. 44/2,656 1.66 8/10 80.00 47/63 ?4.60 A. falcata 56/4850 1.15 10/25 40.oo 169/288 58.68 A. gardneri 201/9,?00 2.07 ...... 115/141 81.56 A. nuttallii 41/1,200 J.42 ...... 23/33 69.70 A. obovata 1,595/4,360 36,58 20/20 100.00 20/20 100.00 A. tridentata 715/16,915 4.23 28/40 70.00 111/156 71.15 A. welshii 91/4,940 1.88 31/48 64.58 37/43 86.05 -3 V1 176 surrounding the frllit. Hinda.ni (1957) suggested that the hardness of the bracts was due to dense masses of interlocking crystals of calcium oxalate. To test for mechanical resistance to germination in the species of the!• ga.rdneri oomplex, the fruiting bracts were mechanically removed by using an Exa.cto knife. Care was taken not to damage the seed coat. As shown in Table 48, the germination or seeds which were removed from their bracts was increased several fold over that of the seeds still encased in the bracts. Jones (1971) showed that the germination in annual Atriplex of Great Britain was much higher after the seed coat was pricked by a. needle. Varying this suggestion, excised fruits of!• corruga.ta were scarified with sandpaper. Earlier observations of the germi- nation of damaged seeds, which had been excised from their bracts, indicated that the embryo would push out of the testa wherever there was a break. When the testa wa.s fractured near the middle of the embryo, the embryo would swell and push out this orifice, usually ca.using the embryo to break at that point. However, when the testa was removed from around the radicle tip, germination was significantly increased over the unscarified control. TA:BLE49. Ge:rmination of excised seeds of!• corrupta after scarification with sandpaper Treatment Germination% Fruits not scarified 10.81 Fruits scarified with sandpaper 13.15 Fruits with testa mechanically removed from ra.dicle 63.44 177 These results suggested that the best way to get maximum germination wa.s to excise the fruits from their bracts and then prick the radicle tip (see Table 48). The percentage germination of these excised and pricked seeds is much higher than that of either the seeds that were still encased in their bracts or those that were only excised from the bracts. Many of the fruits which were opened did not contain seeds. In these the empty bracts developed normally and were indistinguish- able from the filled ones. Table 48 shows the highest fruit fill was 62 percent in - A. obovata and the lowerst was 7 percent in -A. cuneata ssp. introgressa.------ Since the fruiting bracts were so ha.rd, much effort was required for removal of each seed and many of them were damaged during the excising process. To be sure that only the filled bracts would need to be cut, fruits were first x-rayed and then only the filled ones cut. The estimate of fruit fill as determined by x-ray correlated fairly closely to that determined by cutting (see Table 50). Two disadvantages of the x-ray method were that some species could not be scored for seed fill and that it was time consuming (although less so than cutting). The most likely reason that some species cannot be read by x-rays is the presence of heavy deposits of calcium oxalate in their bracts • .Another method wa.s developed which allowed quick, easy separation of empty and filled fruits. As shown in Table 51, when the fruits were floated in 95 percent ethanol, a high percentage of filled .fruits sank, while most of the empty ones floated. TABLE 50. Seed fill in the su:f'frutescent shrubs in the genus Atriplex determined by x-r~ photographs and by cutting open X-ray analysis Cutting analysis Species Number of Total Total Percent Number of Total Total Percent sources fruits filled filled sources fruits filled filled !• acanthoca.rpa • • • • • • • • • • • • 2 88 53 60.23 !• corrugata 11 4460 931 20.87 12 3044 576 18.92 !• cuneata 17 4185 1022 24.42 12 1990 340 17.09 !• cuneata ssp. introgressa ,1 400 61 15.25 16 2544 173 6.80 !.• falcata 6 3000 259 8.63 39 3960 516 13.03 !• gardneri • • • • • • • • • • • • 15 1356 156 11.50 !• nuttallii • • • • • • • • • • • • 4 236 36 15.25 !• obovata 4 798 538 67.42 1 162 100 61.73 !• tridentata 2 6885 1155 16. 78 15 1903 372 19.55 !• welshii 1 3380 1863 55.12 2 354 188 53.11 ..... -.J 0) 179 Several methods were tried to increase the germination percentage of bract-encased fruits. Treatments with various concentrations of thiourea, gibberelic acid, and sulfuric acid .failed to show a:ny increase in germination rate. These results were con.firmed in!• canescens by Leslie, et al. (1974). The best method discovered so far .for improving germination in most species appears to be mechanical removal o.f the bract. In some species this can even be accomplished by grinding of the .fruits in a hand food grinder. As shown in Table 48, although the seeds were excised and the testa removed from the radicle tip, some seeds still failed to germinate. To determine whether such fully developed seeds which did not germinate were viable, samples of them were tested with tetrazolium. chloride. Both Colby, et al. (1961) and Springfield (1970) had previously used this test to indicate the percent viability of seed sources. In the presence of tetrazolium chloride, living tissue stains red, whereas, non-living or weak tissues do not. Thus, respiring tissue is capable o.f changing this colorless tetra.- zolium dye into highly-colored compounds by chemical reduction. Table 52 shows that the viability of Atriplex seeds determined by the tetrazolium chloride test ranges from 70 percent in!• cuneata and !• ao.cruga.ta to 100 percent in !• ga.rdneri. When the staining patterns were compared with the percentage of germination, the results showed that only those seeds which stained at the radicle tip germinated (see Figure 50). The principal advantages of this method are that the results are available in hours rather than in weeks, as is the case in 'l'Al3LE51. Separation of filled fruits* of Atriplex by flotation in 95% ethanol Random sample Top sample Bottom sample Species Location # II II filled % filled 'lo filled % !• ei:ardneri 16 miles north Rawlins, v/yoming 1/79 1.27 0/51 o.oo 30/140 21.43 79 miles west Casper, Wyoming 1/89 1.12 1/156 0.64 27/101 26.73 !• falcata 4 miles east Nevada-Utah Border on Hwy 30 0/26 o.oo 0/41 o.oo 8/79 10.13 8 miles west :MudLake, Idaho 2/112 1.79 • • • • • • 4/18, 22.22 27 miles west Austin, Nevada 7/60 11.67 • • • • • • 20/59 33.90 15 miles south Wells, Nevada 10/104 9.62 • • • • • • 10/64 15.63 Flook Lake, Hart Antelope H.efuge, Oregon 1/141 o. 71 • • • • • • 9/17 52.94 ...-Seedfill determined by cutting open the protective bracts. ()).... 0 181 germination tests, and that the viability of even dormant seeds can be determined. Thus, the test gives an estimate of potential germi- nation, which is especially valuable when seeds in the Atriplex complex show varying degrees of dormancy or a.£ter-ripening. The potential germination percent is defined as the percent viable seeds times the percent filled fruits. As shown in Table 53, if this interpretation is valid, the highest expected germination for !• corrugata would be 13.29 percent. Two separate experiments, one on_!. corrugata·a.nd the other on!• welshii, were conducted on the products of fruits cut out from their protective bracts. Many of the seeds which were examined were shriveled up, with no apparent development of endosperm. To determine if any of these were viable, plump and shriveled seeds were tested for viability with tetrazolium chloride. In!• welshii, 49.4 percent were fully developed seeds. These showed 92.6 percent of the seeds as viable. The seeds lacking endosperm were infrequent, 0.006 percent, and failed to indicate any viability by staining. Atriplex corrugata showed 24.8 percent fully developed seeds and 38.7 percent developed seeds lacking endosperm • .Amongthe filled seeds, 70.4 percent were considered viable; none of the seeds lacking endosperm was viable. The testing results indicated that the number of empty seed coats varies greatly between species and that either genetic instability, such as polyploidy, or environ- mental shocks, such as freezing or frost, could account for their lack of endosperm (see Table 54). A number of factors might be responsible for the lack of complete seed implantation. Those fully developed bracts with 182 TABLE52. Viability of Atriplex seeds as determined by testing with tetrazolium chloride Humber of Humber of Humber of % viable Species sources seeds treated via.bl_e seeds seeds !• corrugata 4 279 196 70.25 !• cuneata 4 216 150 69.44 !• falcata 2 81 70 86.42 !• ga.rdneri 1 9 9 100.00 !• obovata 1 50 41 82.00 !• tridentata 4 120 108 90.00 !• welshii 2 77 73 94.81 183 STAIN RATING [7mm 0 . .. . 1 r ( . . . ' . 2 ( , 3 r r 4 Fig. 50. Staining patterns of excised seeds treated with 0.1 percent tetrazolimn chloride. All seeds that showed some staining in the radicle tip area are considered viable. 184 TABLE 53. Potential seed germination of each species in the Atriplex gardneri complex as determined by seed fill and seed viability Species % % Potential filled fruits viable seed germination !• corrugata 18.92 70.25 13.29 !• cuneata 17 .09 69.44 11.87 !• falcata 13.03 86.42 11.26 !• gardneri 11.50 100.00 11.50 !• obovata 61.73 82.00 50.62 !• tridentata 19.55 90.00 17.60 !• welshii 53.11 94.81 50.35 185 aborted seeds may have resulted from insect damage, genetic incom- patibili ty-, detrimental environmental influences, or just lack of pollination. Those seeds having fully developed bracts and seed coats but lacking endosperm probably resulted from developmental damage or genetic incompatibility, though there was apparently enough embryo development to stimulate the formation ot the seed coat {see Table 54). Polyploidy certa.:i.nly could account in part for the low fruit fill in some of the species. As indicated previously, most of the species in this complex are polyploids. If they were autoploids or segmental alloploids, then multivalent pairing would reduce fertility • .Although little is known of the nature of the ploidy in this complex at the present time, its commonocC'llffence is likely a contributing factor to reduced seed fill. Table 55 shows fruit fill to be generally higher in the diploids tha.t 1n tetraploid forms of!• falcata., !• gardneri, and!• ouneata. This, however, differs from a stuc:cy,conducted by Mc.Arthur and Pope (1975) on selected species of Artemisia. The proposed autotetraploid species failed to show a reduction in germination as com.pa.redto the diploid species. It is quite possible that insect damage is one of the causes for low seed fill. ill species of Atriplex appear to be susceptible to infestation by insects. Three species of insects were fOUJ1dto be associated with all seven Atriplex species in this complex; they are as follows: immature Remiptera, Thysanoptera (Family Phloeothripipidae) or thrips, and Tetranychidae (spider mites). Most of the seed damage is likely caused by thrips and spider mites. The 186 TABLE54. Reduction in seed fill as indicated by the number of fully developed seed coats that lack endosperm and/or embryos* Total affected Number of Species sources Range(%) Sample y; size !• acanthoc¥Pa 1 10/73 13. 70 • • • !• corrugata 7 217/1564 13.87 3.13-15.53 !.• cuneata 10 113/1943 5.82 0.00-22. 77 !.• cuneata ssp. introf/ia:'.essa 10 565/2041 27.68 0.00-65.28 !.• falcata 23 179/2770 6.46 0.00-32.22 !• s;ardneri 18 150/1704 8.80 0.00-31.71 !.• nuttallii 3 9/135 6.67 0.00-14.29 !• tridentata 10 59/574 10.28 0.00-48.39 !.• welshii 3 32/320 10.00 4.38-20.00 -fE-Otherexperiments showed these seeds failed to germi- nate or stain with tetrazolium chloride. 187 TABLE55. Seed fill in diploid and tetraploid populations of certain Atriplex species. Seed fill Chromosome Species level Sample size % !• falcata. :Diploid 494/3516 14.05 Tetraploid 44/888 4.95 !• gardneri Diploid 42/424 9.91 Tetraploid 141/1202 11.73 !• mmeata Diploid 54/151 35.76 Te trap lo id 325/1948 16.68 188 thrips lay eggs in the flowers and then permit the bracts to grow around them. Spider mites spin a web which encases the entire inflorescence (see Table 56). In the Chenopodiaceae there are a number of instances in which the presence of inhibitors in the seed or in some other structure have been responsible for the reduced germination. In there are inhibitors present in the perianth (Stout, et al, 1941) which delay not only germination of the~ seed, but also other seeds in the vicinity. Koller (1957) bas found that in!• dimorphostegis, germination is inhibited by a diffusion from the braoteoles. The experiments in this study all clearly indicate that excised seeds germinate readily, while unexcised seeds fail to germinate because of some inhibiting properties of the bracts, either mechanical or chemical. Treatment of each of the excised seeds with its own leachate completely suppresses all germination. However, !, obova.ta showed some germination in the weaker extracts. Inhibition caused by chemicals in extracted leachates was expressed in several ways in excised seeds. In some cases the radicle would begin to emerge and then turn black or just cease to respond. In others, it emerged but failed to develop root hairs. Both root-tip elongation and elongation of the root hairs were about one-half as much as in the control. To determine the relative effect of the inhibitor on other species, the leachate of selected species was also applied to germinating radish and lettuce seeds. As shown in Table 57, the extracts from seeds of!• cuneata ssp. introgressa, !• ga.rdneri, 189 TABLE56. Reduction in seed fill as a result of visible insect damage Total damaged Number of Range(%) Species sources Sample c1 size /0 !• aca.nthooarpa 1 0/73 o.oo • • • !• oorrge;ata 4 105/764 13.74 0.62-67.40 fl• cuneata 4 18/287 6.27 0.00-15.91 !• cuneata ssp. intro~essa 9 89/1898 4.69 0.00-17.29 !• falcata. 23 296/2394 12.36 0.00-37.74 !• s:ardneri 18 260/1704 15.26 0.00-39.02 !• nut tall ii 3 42/135 0.31 0.00-30.46 !• tridentata 9 39/566 6.89 0.00-35.40 !• welshii 3 12/320 3.75 0.31-11.76 190 !• welshii, and!• obovata show only a slight inhibition on lettuce and radish germination. Strong inhibition was expressed in leachates from!• tridentata, !• corrugata, !• falcata, and!• cuneata. Consequently, the inhibitor of each species is most effective on its own germinants. To summarize, there are at least four germination inhibitors present in this complex of Atriplex species. First, and probably the most effective, is the mechanical barrier of the bracts. As suggested by Vest (1952) for!• confertifolia, this is most likely overcome in nature by fungal activity, primarily several species of Altenaria. In these studies, fungal spots were observed on the bracts in nearly every species. The second apparent inhibitor is that of the water soluble leachate as suggested by Went (1955). This inhibitor most likely is removed when sufficient precipitation is available for germination. Torell and Ha.as (1959) found such an inhibitor in salt sage of southern Idaho. The third inhibitor, also observed by Jones (1971) in annual Atriplex, is the impermeability of the testa in some species. For instance, tetrazolium chloride failed to enter the embryo unles the testa had been previously ruptured. Fourth, though not strongly substantiated, is an inhibitor effect inside the seed coat. As shown above, only after removal of the testa from the radicle end did the seeds germinate. A gelatinous material inside the testa and at the radicle tip has been observed and is probably involved in this inhibition. The testa, like the bracts, is likely broken down by bacterial action and this inhibitor either leached away or oxidized. 191 TABLE57. Inhibitory effects of Atripie; le!l,Chat.as on germination of lettuce and radish seeds (numbers indicate germination of four replications of n=25; samples were averaged) # of germina.nts' , Leachate Species strength Radish Lettuce !• corrugata 1:0 1 8 1 :3 12 24 1:5 16 20 1 :10 23 23 !• cuneata 1:0 0 0 1:3 6 23 /\ 1:5 19 23 t :10 22 23 !• cuneata ssp. introgressa 1:0 21 23 1 :3 25 22 1:5 25 25 1 :10 25 23 !• falcata 1:0 0 0 1:3 12 25 1 :5 19 21 1 :10 24 19 !• gardneri 1:0 23 22 1:3 25 20 1:5 24 24 1 :10 25 24 192 TABLE57. Continued # of ger.mi.nants. Leachate Species strength Radish Lettuce !• obovata 1 :0 23 21 1 :3 25 19 1:5 23 21 1 :10 24 22 !• tridentata 1:0 8 8 1 :3 . 18 23 1 :5 23 21 1 :10 24 24 !• welshii 1:0 24 23 1 :3 24 · 24 1 :5 25 20 1 :10 24 23 193 Seedling Analysis Phenological observations were ma.de on hypocotyl length, cotyledon length, epicotyl length, and total plant height in five species of Atriplex (see Table 58). The most distinct character appea.rs to be the elongation of the hypocotyl. As shown in Fig. 50, two distinct rates of hypocotyl elongation are suggested. Atriplex p;a.rdneri, !• tridentata, and!• obova.ta have hypocotyls that elongate both rapidly and extensively;!• cuneata and!• t'alcata show reduced hypocotyl growth rates. !• obova.ta was observed to be the first to germinate, establish an extensive root system, display its coty- ledons, and initiate epicotyl growth. 194 TABLE58. Phenological observations in five species of Atriplex Total Species Populations sample · 3 days number 1 2 3 4 !• cuneata 1 mile east Thompson, Utah 3 l!• falcata 1.5 miles southeast Woodruff, Utah 3 !• gardneri Laramie, Wyoming 3 4 miles south Manderson, Wyoming 1 50 miles north Casper, Wyoming 5 Circle, Hontana 4 10 miles east Hinsdale, Montana 5 !• obovata 5 miles east Shiprock, New Mexico 22 9 Mexican Border 44 4 1 mile east Winslow, Arizona 21 5 10 miles south Deming, New Mexico 50 8 Palomos, Mexico 40 6 !• tridentata 1.5 miles south Sigurd, Utah 3 4 miles west Ephraim, Utah 8 7 South Wendover, Utah 2 *Characters measured are as follows: 1. Itrpocotyl length in mm. 2. Cotyledon length in mm. 3. Total height in mm. 4. Epicotyl length in mm. 195 TABLE 58. Continued Characters mea.sa.-reia.nd time periods 6 days 8 days 10 days 14 days 24 days .1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 3 4 6 4 5 8 4 8 11 4 8 11 2 3 3 3 6 0 8 5 13 11 6 15 12 6 15 13 6 15 0 2 3 5 20 8 26 26 9 35 1 29 11 40 20 4 10 7 14 13 8 22 17 8 22 17 10 24 1 4 4 5 9 6 5 10 6 6 11 7 8 13 1 3 3 4 9 5 6 9 9 10 16 1 11 6 11 7 12 12 7 16 12 7 16 1 12 9 19 4 5 7 7 10 14 7 10 18 10 11 20 2 10 12 20 7 7 4 7 5 9 7 5 9 8 5 9 8 8 9 2 9 7 9 8 15 11 8 15 11 8 15 1 11 11 16 6 8 7 8 8 9 8 9 9 9 9 10 2 10 11 18 4 4 6 7 9 7 8 14 7 11 14 8 12 15 1 10 5 10 6 13 13 6 15 14 7 6 1 14 7 21 3 11 7 16 13 7 20 16 7 20 22 9 27 0 196 A. gardneri 15 A. tridentata 10 A. obouata 5 A. cuneata • • A. falcata 1 2 6 10 14 18 22 DAYS Fig. 51. lzypocotyl elongation in five species of Atriplex. CHAPTERVI GENETICSTUDIES Materials and Methods An analysis was made of th~ amount of morphological variation present in each species, population, and plant. Herita- bility estimates of each character within each population were computed from multivariate analysis printouts by removing all of the within-plant variation and then analyzing only the between-plant variation. This between-plant variation was expressed for each character as an upper limit of the amount of variation due to the genetic background of each population. Because all of the environ- mental variation between plants was probably not removed, some commongarden materials were also analyzed for certain populations as a methods check. The population heritability estimates for each character were then pooled to give species heritability estimates. Observations were taken in the field as to the amount of rootsprouting and layering present in each population. The root- sprouting was checked in the most homogeneous pocket of each population by digging up plants and tracing their horizontal roots. La¥ering was simply detected by lifting the lower branches of several plants and checking for the formation of adventitious roots. 197 198 Sex-ratio observations were also taken within ea.eh popu- lation. The sex ratio was scored from a belt transect approximately 3 by 20 feet. If an unusual sex ratio was observed, several additional transects were checked. One permanent transect was established in 1974 east of Green River, Utah, in a population of .!• corrugata. Twenty female plants were marked with aluminum tags, while twenty male plants were marked by using red pa.per tags. The transect was read again in 1975. Hybridization of transplanted material was conducted in the spring of 1973 in the greenhouse. As plants came into flower, they were isolated and crossed with other flowering material. The fruiting bracts were collected in the fall and either analyzed for seed fill or planted in soil in seedling flats. Most of the green- house material failed to flower in 1974 and 1975, and, therefore, minimal hybridization work was conducted. Results and Discussion Heritability The!• ga.rdneri complex is a polymorphic species and great variation is found among populations as well as within populations. For instance, according to Hall and Clements (1923), fruiting bracts vary to so great an extent that the population extremes seem to be present in the variation of a single plant, i.e., smooth to strongly tuberculate or sessile to long-stalked fruits are all present on the same plant. Much of this vast morphological variation is, undoubtedly, an expression of different environmental influences. However, as suggested above, in both the morphological and 199 ecological studies, populations are sufficiently different t.o be considered ecotypes, retaining their distinctiveness even in a commongarden. Furthermore, when plants were tested for their differences in each population, it was found that the within-plant variation for most measured characters was much less than the between-plant variation. This suggests that many of the differences expressed for both plants and populations could be attributed to their genetic backgrounds. Heritability estimates, between-plant variation with within- plant variation removed, were computed for each character within each population (see Tables 59 to 66). Those characters in each population which showed statistically more between-plant variation than within-plant variation at •=.05 are marked by an asterisk. For instance, as can be seen in Table 59 for!• faloata from Mud.We, Idaho, only four characters have more variation within the plants than. among the plants. If this is a fair estimate of the difference among populations, then the species average column in each table is an additional support to the theory that each popu- lation is genetically distinct. For example, as noted in Table 59, each of the characters from all populations, when contrasted one at a time, appears to be statistically different. Table 67, a summary table, gives suggestions as to the possible genetic influence on each measured character. Almost all of the average heritability percents for each measured character of each species are statistically different at oc•• 05. This supports the findings of the discriminant analysis program in suggesting that all of 200 TABLE59. Percent heritability estimates of leaf and fruit charac- ters in,!. falcata Percent heritability Characters Mud Lake, Idaho Grouse Creek, Utah Leaf length 31. 7* 79.0* Leaf width 39.9* 87.3* Petiole length o.o 22.3* Leaf 1/w ratio 12.6 81.1* Leaf angle 29.7* 62.5* Percent petiole 1.5 27 .2* Fruit length 43.0* 7.9 Fruit width 47.4* 9.8 Fruit depth 15.1 o.o Fruit pedicel length 59.7* 21.7 Fruit beak length 23.9* 3.8 Fruit beak width 20.4* 13.4 # fruit shoulders 25.0* 100.0* # fruit tubercules 59-.4* 48.4* Fruit 1/w ratio 30.4* 15.4 *Plant means a.re signi.fica.ntly di.fferent at oe=-.05. 201 TABLE59. Continued Percent heritability Species Austin, Nevada Wells, Nevada eye Patch Res. , Nevada average 83.5* 75.2* 77.9* 69.5 86.3* 69.0* 87.8* 74.1 42.8* 58.4* 62.8* 37.3 63.1* 65.5* 79.7* 60.4 39.2* 63.2* 70.7* 53.1 36.4* 52.0* 56.3* 34.7 35.1* 26.8* 86.3* 39.8 27.0* 67.3* 32.6* 36.8 44.3* 36.9* 34.3* 26.1 o.o 7.2 70.1* 31.7 37.8* 3.8 67.4* 27.3 o.o 52.9* 80.1* 33.4 100.0* 100.0* 100.0* 85.0 37.4* 7.7 37.5* 38.1 13.0 75.6* 25.3* 29.9 202 TABLE60. Percent heritability estimates of leaf and fruit characters in!• welshii Percent heritability Characters Species Cisco, Utah Green River, Utah average Leaf length 76.1* 83.0-l<· 79.6 Leaf width 54.7* 46.2~,· 50.5 Petiole length 3s.o·~ 66.6-l(• 52.3 Leaf 1/w ratio 33.3-x• 45.2* 39.1 Leaf ancle 28.9* 69.2* 49.1 Percent petiole 56.G* 61.y-<· 59.0 Fruit leneth 73.8% 65.1% 69.5 Fruit width 58.5-l<· 14.7 36.6 Fruit depth 27.1* 9,.7 18.4 Pedicel length 7 .1 52.9* 30.0 Fruit beak length 58.2* 48.5* 53.4 Fruit beak width 43.0-l<· 33.2¾:· 38.1 // fruit shoulders '14.4* o.o 27.2 # fruit tubercules 40.0* 15.7 27.9 Fruit 1/w ratio 44.0* 28. 9-r.- 36.5 *Plant means are significantly different at0(=.05. 203 TAJ3LE61. Percent heritability estimates of leaf and fruit characters in!• cuneata ssp. introgressa Percent heritability Characters Wellington, Utah Leaf length 25.1i-:· Leaf width 73.9* Petiole length 10.5 Leaf 1/w ratio 81.0* Leaf angle 66.5* Percent petiole 6 ..9 Fruit leI1t,o-th 58.3* Fruit width 58.5i<· Fruit depth 49.4* Pedicel length 47.4* Fruit beak length 26.4* Fruit beak width 54.0* # fruit shoulders 54.5* 'if fruit tubercules 50.0* Fruit 1/w ratio 47.6·X· *.f'.lant means are significantly different at ac.=.05. 204 TABLE62. Percent heritability estimates of leaf and fruit characters in!,. cuneata (2n=18) Percent heritability Characters 3 miles south 16 miles south Species Bonanza, Utah Bonanza, Utah average Lea£ length 64.9* 65.4* 65.2 Lea£ width 59.7* 71.9* 65.a Petiole length 58.3* 76.1* 67.5 Leaf 1/w ratio 67.0* 54.6* 60.8 Lea£ angle 62.0* 40.7* 51.4 Percent petiole 58.2* 52.0* 55.1 Fruit length 31.6* 62.0* 46.8 Fruit width 28.8* 79-5* 54.2 Fruit depth 58.8* 52.4* 55.6 Pedicel length 24.1* 47.8* 36.o Fruit beak length 5.s 37.6* 21.7 Fruit beak width o.o 18.3 9.2 # fruit shoulders 100.0 100.0 100.0 # fruit tubercules 72.0* 31.1* 51.6 Fruit 1/w ratio 17.2 64.3* 40.a *Plant means are significantly different at ct=.05. 205 TABLE63. Percent heritability estimates of leaf and fruit characters in -A. cuneata (2n=36) Percent heritability Characters B:nery, Green Iµver, Price, SJ?,ecies Utah Utah Utah average Leaf length 73.1* 47.0* 79.3* 66.5 Leaf width 54.0* 75.4* 82.7* 10.1 Petiole length 47.4* 53.5* 68.0* 56.3 Leaf 1/w ratio 51.1* 71.2* 57.2* 59.8 Leaf angle 25.5* 63.5* 70.1* 53.0 Percent petiole 16.7 36.2* 45-9* 32.9 Fruit length 59.6* 44.5* 26.6* 43.6 Fruit width 36.1* 1.5 20.8 19.5 Fruit depth 32.5* 19.1 32.9* 28.2 Pedicel length 42.4* 72.8* o.o 3a.4 Fruit beak length 41.8* 44.7* 79.8* 55.4 Fruit beak width 13.2 63.7* 13.5 30.1 # fruit shoaj.ders 3.8 1.9 35.0* 13.6 # fruit tubercules 60.6* 33.3* 40.5* 44.8 Fruit 1/w ratio o.o 4.7 12.0 5.6 *Plant means are significantly different at OC=.05. 206 TABLE64. Percent heritability estimates of leaf and fruit characters in!• ga.rdneri Percent heritability Characters Lovell, Wamsutter, Saco, Wyoming Wyoming Montana Leaf length 61.1* 59.3* 72.9* Leaf width 25.9* 76.4* 91.3* Petiole length 29.8* 37.4* 31.1 * Leaf' 1/w ratio 17.2 60.4* 89.5* Leaf angle 40.6* 23.8* 78.1* Percent petiole 11.0 11.6 2.9 Fruit length 60.5* 23.5* 70.4* Fruit width 47.2* 7.4 76.8* Fruit.depth 56.:l* 6.8 46.6* Pedicel length 67.6* 29.7* 48.3* Fruit beak length 1.9 23.7* 37.8* Fruit beak width 10.5 56.2* 46.6* # fruit shoulders 40.7* 56.8* 74.0* # fruit tubercules o.o 77.8* 80.5* Fruit l/w ratio 8.6 24.7* 84.9* *Plant means are significantly different at •=.05. 207 TABLE64. Continued Percent heritability Casper, Cana.dia.n- Casper, Red Desert, Species Wyomi~* USA Border Wyoming-lH'-'-+ Wyoming average 34,8* 79.s-r.- 52.2·l} 78.0* 62.6 76.6* 74 .4-x- 74.4* 83.5* 71.8 52.2~~ 53.2* 73.0* 47-9* 46.4 44.s-::- 66.5·1e 45. 7-:+ 66.2* 55.8 64.5* 73.4-x- 57.1* 67.5* 57.9 47.6* 39.2* 68. )"'0 29.9* 30.1 66.871' 67.3* o.o 37.0* 46.5 s4.a-.." 59. 9,-:- 24.4-t:· 49.8* 50.0 67.7* 22.2 2 .C,., o.o 28.9 31.9* 52.7* 41.5* 3.6 39.3 22.5* 57.6* 18.2 64.4* 32.3 13.5 21.1 30.0-x- 59-7* 33.9 73-4* 4,8 71.9* 67.6* 41.8 45.8* 32.8-l<· 19.G 78.5* 47.9 92.p· 7.0 45.2~~ 23.6* 41.1 -IHESOmiles north Casper, Wyoming -IHHi-50miles west Casper, 'v/yoming 208 TABLE65. Percent heritability estimates of leaf and fruit characters in!• tridentata Percent heritability Characters Ephraim, Utah Salina, Utah Leaf length 84.2* 44.0* Leaf width 79.5-'A· 59.7* Petiole length 65.0* 18.1 Leaf 1/w ratio 45.6* e.6 Leaf angle 35.5* 14.8 Percent petiole 52.8* 22.5* Fruit length 23.0* 74-4* Fruit width 19.8 73.4* Fruit depth 35-7* 25.4* Pedicel length 31.0* 22.5* Fruit beak lel'lt.,~h 32.0* 47.9* Fruit beak width 62.0* 58.0* # fruit shoulders 59.6-¥: 56.2* # fruit tubercules 63.0* 61.3* Fruit 1/w ratio 99.3* 59.2* *Plant means are significantly different at «=.05. 209 TABLE65. Continued Percent heritability Sigurd, Utah Species Grantsville, Utah Austin, Nevada average 77.7* 51.4* 83.1* 68.1 68.1* 51.5* 50.6* 61.9 10.1 o.o 49.9* 28.6 84.2* 41.3* 72.1-i;. 50.4 58.0* 56.3* 54.4* 43.8 29.5* o.o 27.2* 26.4 59.5-r.- 45.4-:t- 30.7* 46.6 81.9* 59.7* 29.2* 52.8 46.4* 58.4* 37.1* 40.6 46.8·* 5.4 78.2* 36.8 40.9* 65.6* 8.4 39.0 80.7* 56.8* 20.9 55.7 43.8* 48.2* 76.1* 56.8 57.0* 35.6* 74.6* 58.3 75.7* 32.6* 21.1 57.6 210 TABLE66. Percent heritability estimates of leaf and fruit characters in A. corrugata Percent heritability Characters Wellington, Cisco, Vernal, Species Utah Utah Utah average Leaf length 70.2* 37-5* 88.7* 65.5 Leaf width 57.0* o.o 63.2* 40.1 Petiole length 48.2* ·40.2 77.0* 55.1 Leaf 1/w ratio 76.1* 17.3 39.9* 44.4 Leaf angle 27.2* 3.9 51.6* 27.6 Percent petiole 48.2* 32.7* 73.0* 51.3 Fruit length 16.3 16.2 57.6* 30.0 Fruit width 51.6* 17.1 26.1* 31.6 Fruit depth 21.0 58.9* 30.6* 36.a Pedicel length 34.4* 38.1* 27.2* 33.2 Fruit beak length 46.1* 28.2* 22.3 32.2 Fruit beak width 52.4* 2.5 50.3* 35.1 # fruit shoulders 100.0* 100.0* 100.0* 100.0 # fruit tubercules 52.7* 1.3 48.8* 34.3 Fruit l/w ratio 44.6* 6.6 54.0* 35.1 *Plant means axe significantly different at ot=.05. 211 TABLE67. Suzmna.ry-of percent heritability estimates in species of Atri:elex Percent heritability Characters !• ouneata ssp. !• falcata !• welshii intro5essa Lea.f length 69.5 79.6 25.1 Lea.f width 74.1 50.5 73.9 Petiole length 37.3 52.3 10.5 Leaf 1/w ratio 60.4 39.1 81.0 Leaf angle 53.1 49.1 66.5 Percent petiole 34.7 59.0 6.9 Fruit length 39.a 69.5 5a.3 Fruit width 36.8 36.6 5a.5 Fruit depth 26.1 18.4 49.4 Pedicel length 31. 7 30.0 47.4 Fruit beak length 27.3 53.4 26.4 Fruit beak width 33.4 38.1 54.0 # fruit shoulders 85.0 27.2 54.5 # fruit tubercu.les 38.1 29.9 · 50.0 Fruit 1/w ratio 29.9 36.5 47.6 212 TABLE67. Continued Percent heritability A. cuneata- A. cuneata - 2n=18 - 2n=36 !• ga.rd.neri !• tridentata !• co?-1:'}lB\ata 65.2 66.5 62.6 68.1 65.5 65.8 10.1 71.8 61.9 40.1 67.5 56.3 46.4 28.6 55.1 60.8 59.s 55.s 50.4 44.4 51.4 53.0 57.9 43.8 27.6 55.1 32.9 30.1 26.4 51.3 46.a 43.6 46.5 46.6 30.0 54.2 19.5 50.0 52.8 31.6 55.6 28.2 28.9 40.6 36.8 36.0 38.4 39.3 36.8 33.2 21.7 55.4 32.3 39.0 32.2 9.2 30.1 33.9 55.7 35.1 100.0 13.6 41.8 56.e 100.0 56.6 44.8 47.9 58.3 34.3 40.a 5.6 41.1 57.6 35.1 213 the measured characters a.re important in separating the individual species. Rootsprouting Further evidence of genetic differences among species has come from field observations. It was noted that some species consistently express rootsprouting as an asexual means of repro- duction, while other species do not. Rootsprouting, the tendency for horizontal creeping roots to initiate buds and give rise to new plantlets, has been observed in the following species: !• cuneata (2n=36), !• falcata, A•ga.rdneri, !• cuneata ssp. introgressa., and !• tridenta.ta (see Table 68). Similar observations were made by Russey (1967) and McLean (1953) for A• ga.rdneri and Nord, et al. (1968) and Windle (1960) for!• tridentata.. However, on only two of these species,!• falcata and A•tridentata, was rootsprouting observed to be very frequent; both appear to have a relatively high frequency of rootsprouting in each of their populations. It was also observed, in almost all populations where rootsprouting occurred, tha.t the lateral root connections between the sprouted clones did not persist over several years. Older sprout connections which were decaying almost always contained ter- mites which severed the clone connections, thus separating the plants. L9¥ering The tendency for layering, the rooting down of stems by the development of adventitious roots, was also noted in the field as 214 TAELE68. Rootsp;routing and.layering.in species of the 0!;. ga.rdneri complex Species Root sprouting Layering !• corrugata None Eictensive !• cuneata (2n=36) Bare Extensive !• falcata Extensive None !• ga.rdneri Minimal Ex:tensive !• cuneata ssp. introgressa Minimal Minimal !• nuttallii Not observed Minimal !• tridentata Extensive Only when erect stems a.re covered welshii None Only when erect A· stems are covered 215 being species specific. All species in this complex, except!• falcata, layer to some extent when their stems a.re covered with soil (see Table 68). Even under ideal conditions, A. faleata plants do not layer. Atriplex cuneata, 2n=36, !• corr;ueta, and!• gardneri layer extensively.•a.nd ofttimes appear to propagate asexually by this means. When the plants become large, the center dies out, leaving a scattered ring of individual plants. Many populations were also observed which failed to layer, especially in a.reas where grass plants were abundant. This most likely was due to the failure of of the stems to become covered because of the minimal amoung of erosion. Sex Determination and Ratios In the fall of 1973, several female plants of both!• ga.rdneri from one mile east of Rock Springs, Wyomingand!• cuneata ssp. il\tros;essa from one mile south of Wellington, Utah, were collected and labeled. The following spring when the plants flowered in the greenhouse, one plant from each location was entirely ma.le. These results posed two important questions: What is the sex ratio in different species? What is the sex determination mechanism? As shown in Table 69, monoecious plants appear to be much more commonthan previously reported by Hall and Clements (1923), Hanson (1962), or Vosler (1962), ranging in average from o.o percent in!• welsbii to 25.9 percent in the diploid!• §uneata (also see Table 70). Most of the species have several monoecious plants in eaoh population, although!• welshii appears to be entirely TABLE69. Sex ratio in the Atriplex 5ardneri complex Sex ratio Numberof Female Male Monoecious Non-flowering Species sources # % # % # % # ~& !• corrugata 1 145/461 31.5 67/461 14.5 57/461 12.4 192/461 41.6 !• cuneata (2n=36) 3 62/141 44.0 48/141 34.0 30/141 21.3 1/141 0.1 !• cuneata (2n=18) 2 58/116 50.0 19/116 16.4 30/116 25.9 9/116 7.8 !• cuneata asp. introgressa 2 120/272 44.1 100/272 36.8 1/272 0.4 51/272 18.8 !• falcata (2n=18) 12 645/1683 38.3 627/1683 37.3 53/1683 3.1 358/1683 21.3 !• falcata (2n=36)* 1 27/153 17.6 25/153 16.3 0/153 o.o 101/153 66.o !• gardneri 12 336/1005 33.4 291/1005 29.0 54/1005 5.4 324./1005 32.2 !• nuttallii 1 42/117 35.9 28/117 23.9 0/117 o.o 47/117 40.2 !• tridentata 3 124/230 53.9 40/230 17.4 1/230 0.4 65/230 28.3 !• welshii 4 134/508 43.5 124/308 40.3 0.308 o.o 50/308 16.2 i!Monoecious plants were not sampled in belt transects, but w~re observed occ~sionally. I\)..... °' 217 TABLE70. Frequency range in mcmoecious·l)lants in species .o:r the !• _ga.-rtU1eri com:2le:x Species Number of in sources Range percent !• corrugata 7 4.76-16.70 !• cuneata (2n•36) 3 5.30-30.80 !• cuneata (2n•18) 2 21.70-28.60 !• cuneata ssp. introgressa 2 0.00-11.20 !• falcata (2ns18) 12 0.00-12.20 !• falcata (2n•36) .1 o.oo -A. gardneri 12 0.00-2.10 !• nuttallii 1 o.oo !• tridentata 3 0.00-0.90 -A. welshii 2 o.oo 218 dioecious. This is contrary to Han.son's thesis (1962), which suggests that 5 percent of the!• welshii plants a.re monoecious. A close examjnation of the monoecious plants showed several patterns of monoeciousness as follows: 1. Predominantly male plants with just a few female fruits developing below the male inflorescence. This is by far the most commonexpression of monoeciousness. In fact, upon very close examlnation of male plants of!• corrpga.ta at Cisco, Utah, it was discovered that 3a.5 percent of them bad one to several female fruits developing below the male inflorescence and 61.5 percent were entirely male. It was also noted that all females were entirely females. Apparently, this is not too uncommonin this genus; Hall and Clements (1923) found that JDa1lY'plants of!• barclaya.na expressed the constant occurrence of at least a few pistillate flowers on predominantly staminate plants. 2. Predominantly male plants with one or two completely female branches. 3. Predominantly female plants with male inflorescences terminating the female flowering stalk. This was observed most emphatically in!• corru,gata in 1974. Apparently, because of excellent precipitation and a relatively mild winter,!• corrue;ata. female plants ea.st of Green River, Utah, terminated their inflores- cences with male glomerules. Nearly 90 percent of the "female" plants, by late July, expressed this bisexuality. Tb.at same year the male plant ratio appeared similar to the 1975 ratio (see Table 219 TABLE71. Sex ratios and descriptions of monoecious plants of selected populations from species in the!• gardneri complex Sex Species Location Female Viale # % # % !• corrugata. 5 miles south 41/83 49.4 30/83 36.1 Cisco, Utah A. cuneata 1 mile east 12/52 23.0 24/52 46.0 - 2n=36 Thompson, Utah 3 miles north- 41/74 55.4 19/74 25.7 east Vernal, Utah A. cunea.ta 3 miles south 34/70 48.6 10/70 14.3 - 2n=18 Bonanza, Utah 10 miles south 24/46 52.2 9/46 19.6 :Bonanza, Utah !• falcata 2 miles south 57/102 55.9 13/102 12.7 Jericho, Utah !• gardneri 24 miles east 50/89 56.2 '29/89 32.6 Wamsutter, Wyoming 50 miles north 37/58 63.8 15/58 25.9 Casper, Wyoming 220 TABLE 71. Continued Ratio Monoecious Non-flowering Description of monoecious plants ,::-f # % ii ,a 8/83 9.6 4/83 4.8 Hostly d' (with a few fruits near bottom of flowering stalk 16/52 31.0 0/50 o.o Laree ?,.plants with just a bra.--ich of d' flowers 13/74 17.G 1/74 1 • ,1 1o/ 1 mostly d' with i below 3/1 3 mostly O'with one or two true branches 20/70 28.6 6/70 8.6 18/20 were mostly d'with ,!lbe low 2/20 were~ with each having only one true ff branch 10/46 21.7 3/46 6.5 10/10 were mostly d' 1/102 0.9 31/102 30.4 Eostly a mixture of cl and S flowers 10/89 11.2 0/89 o.o 9/10 mostly d'with i fruits below 6/58 10.3 0/58 o.o 6/6 mostly c:{with a few S, fruits below 221 69). Similar observations were also noted on!• acanthooar:pa plants that were grown in the greenhouse. 4. Predominantly female plants with only one or two completely male branches. Atriplex ouneata plants east of Thompson, Utah, expressed this pattern in 1974. Male plants here carried only male flowers and small statured female plants bore only female fruits, but ea.ch of the large statured "female" plants had one or two branches with male flowers. 5. A mixture of both male and female flowers on ea.ch flower stalk. This type appears most prominent in!• falcata (see Table 71). Because of possible ser reversal and because of the variable sex patterns observed from year to year, a permanent plot was set up in a population of!• corrpga.ta five miles east of Green River, Utah, in 1974 and twenty male and twenty female plants were tagged. As shown in Table 72, the following results were read from these tagged plants in 1975. TABLE72. Seasonal sex patterns in a permanent plot of!• corrggata Year Female plants Ma.le plants 1974 20 20 1975 14 Females 4 Males 2 Monoecious plants(¼ male, 2 Monoecious plants(¼ male, ¼ female) and mostly ½ female) and mostly ma.le female with some male with female below flowers 3 Non-flowering plants 13 Unrecovered tags 222 Ma.ny-of the paper ta.gs used to iaentify the male plants decomposed over winter. Nevertheless, a.s cen be seen, there was not a complete sex . reversal, but several plants which were dioecious in 1974 were monoecious in 1975. It is conceivable that monoeciousness in plants could be adaptively superior to dioeciousness. Monoecious plants would likely have an increased opportunity for female flowers to . become pollinated, with a corresponding increase in seed fill, which would give them a distinct advantage over dioeeiouq plants. Another possible advantage of monoeciousness over dioeciousness would be , the role it might play in permitting the establishment of polyploidy. Once a monoecious polyploid plant was established, a pollen source would be concomitantly available but would be reproductively isolated in dioecious plants. The mechanism for sex determination in Atriplex appears to be unresolved at this time. A. theory has been advanced, however, which considers the sex determining mechanism in!• canescens. Stutz, et al. (1975) proposed, that in the diploid!• canescens, one sex could be represented by XX and the other XY, the diploid being strictly dioeoious. When the genome wa.s doubled, the plants could be either ma.le or female depending on environmental circumstances. McArthur (1976), adding to the theory of Stutz, p.roposed the sex- determining mechanism in -A. canesoens of XXXXfor pistillate plants, XXYYfor staminate plants, and XXXYfor monoeoious plants and those that vacillate among floral phenotypes from year to year. Such a hypothesis is not helpful here, however, because both monoecious 223 and dioecious plants are found in the diploid populations as well as in the polyploids. Natural and Artificial B;ybrids In addition to showing considerable morphological and ecological similarity, these Atriplex shrubs are also genetically similar. It is not uncommonto find numerous putative hybrids in the field and many of these yield progeny {see Table 73). In an attempt to gain further understanding of these species, plants from selected populations were artificially hybridized in the greenhouse in 1973. The resultant fruits were then germinated in soil-filled flats. As can be seen in Table 74, not one germina.nt resulted from these crosses. The chromosome numbers of each of these plant collections were not known at the time of hybridization. Thus, plants having the most compatible chromosome complements were not necessarily crossed, which could possibly account for the lack of germinants. Another possible reason for the lack of germinants from these crosses could be either inhibition of developed fruits (as indicated above) or the development of empty fruiting bracts. As suggested in Table 75, the development of empty fruiting bracts certainly is a valid explanation. Female plants that were isolated from all pollen sources still developed fruiting bracts, although these were empty. Thus, the hybridization of chromosomally unrelated accessions could possibly result in fruit development regardless of the pollen source. Lack of pollination could also help explain the high frequency of empty bracts in most populations analyzed (see Table 50). 224 TABLE 73. Species in the Atriplex gardneri complex that hybridize with o·cher Atriplox species Species Species with which it hybridizes !• corrue;ata !• cuneata, !• confertifolia !• cuneata !• COz::£M:ata, !• cuneata ssp. intro- g;essa, !• canescens, !• confertifolia !• cuneata ssp. introgressa !• cuneata !• falcata !• gardneri !• confertifolia, !• canescens, ! . :x:!• apt era !• tridentata !• canescens -A. welshii 225 TAELE74. Germination of seeds from a.:rtificia.l hybrids produced' by controlled crosses. Germination E;ybrids # % !• tridentata x-. !,. bonnevillensis Eskdale, Utah Pine Valley, Utah 0/200 o.o !• tridentata X !• bonnevillensis Milford, Utah Pine Valley, Utah 0/27 o.o !• falcata X !• gardneri Woodruff, Utah Rock:Springs, Wyoming 0/250 o.o !• tridentata X !• gardneri Hilford, Utah Rock Springs,- Wyoming 0/50 o.o !• tridentata X !• gardneri Pa.inter Springs, Utah RockSpri'ngS, Wyoming 0/25 o.o !• ac!!!thocaroa X !• gardneri San Roberto Jct., Mexico Rock Springs, Wyoming 0/25 o.o !• gardneri X !• acanthocarpa RockS~ings , ..Wyoming San Roberto Jct., Mex. 0/50 o.o !• acanthocarpa X !• tridentata San Roberto Jct., Hexico Hinckley, Utah 0/10 o.o !• acanthocarpa X !• t:ddentata Sa.n Roberto Jct., Mexico Painter Springs, Utah 0/50 o.o !• acanthocarpa X !• tridentata San Roberto Jct., Mexico Rock Springs, Wyoming 0/20 o.o !• cuneata X !• tridentata Thompson, Utah Painter Springs, Utah 0/70 o.o !• cuneata X !• tridentata Thompson, Utah Hinckley, Utah 0/18 o.o !• cuneata X !• ca.nescens 0/35 o.o Thompson, Utah • • • 226 TABLE 75. Percent seed fill in isolated female plants Seed fill Species Location ii 16 !• cuneata 5 mi. south Emery, Utah o/67 o.oo !• cuneata ssp. introgressa Oarbon-.&lery Co. Line, Utah 0/9 o.oo .!• falcata Desert Mts., Utah 0/27 o.oo !• s;ardneri Lyman, Wyoming 0/12 o.oo !• tridentata 4 mi. west Ephraim, Utah 0/54 o.oo CHAPrERVII TAXONOMICSTUDIES From a review of the morphological, cytological, ecological, phenological, and genetic data recorded above, a taxonomic descrip- tion is summarized for each ta:x:on in the Atriplex ga:r;dneri complex. In order to facilitate easy separation of these species, a taxonomic key is also included. Kezto Species in the Atriplex gardneri Complex Plants usually erect; leaves linear-oblong to spatulate. Fruits heavily tuberculated. Plants with involute leaves and pediceled (2.5 mm) fruits •••••••• (1) !• cuneata ssp. introgressa Plants lacking involute leaves and pedi- celed (0.5 mm) fruits ••••• (2) !• welshii Fruits seldom or moderately tuberculated. Fruits small, fusiform. with a single attenuate beak; flowers in Mc\Y' and early June •••••••• (3) !• falcata Fruits compressed, cuneate, usually with 3 but sometimes 5 shoulders or points; flowers in late June and July ••••••••••••• (4) A• tridentata Plants usually decumbent or ascending; leaves ovate, cuneate, or oblong. Leaves less than 1O mmin length and linear- oblanceolate or oblong •••• (5) A• corrpga.ta 227 228 Leaves longer than 20 mmand cuneate, obo- vate, or rounded ovate. Leaves obovate or obla.nceolate oblong; fruit surfaces generally smooth or lightly tuberculated; Wyoming and Montana •••••••••• (6) !• gardneri Leaves cuneate or rounded ovate; fruits generally heavily tuberculated; distribution restricted almost entirely to Utah and western Colorado. Leaves blue-green, cuneate, less than 20 mmin length and 11 mmin width; occupies soils relatively high in salt ••••••••••••• (7) A. cuneata - (2n=36) Leaves yellow-green, ovate or rounded ovate, greater than 30 mmin length and 18 mmin width; occupies low . salt soils •••••••••• (8) A. cuneata - (2n=18) 1. Atriplex cuneata ssp. introgressa. Hanson. Erect shrub, 1 to 2 dm high, 2 to 3 dm wide, and 2.5 to to 3.5 dm in depth; much branched near the base; branches erect; seldom leyers or rootsprouts; leaves oblanceolate to spatulate, 15 to 24 mm long, 4.3 to 5.5 mmwide, petiole not distinct from blade but expressing itself to 4 mm; flowering mid-April and~; fruiting bracts sessile or on pedicels to 8 mm(average of 2.5 mm}; fruit 7.6 mmlong, 5.0 mmwide, and 4.6 mmdeep; heavily tuberculated (average of 21.1 per fruit) with main apex average length of 3.1 mm. Atriplex cuneata ssp. introgressa, restricted in distri- bution to southeastern Utah, primarily occupies cley to cley loam soils which are relatively low in soluble salts (1185 to 1414 ppm). The tetraploid population located at the Carbon-.&nery County Line on u.s. Hwy6-50, however, tolerates soils higher in soluble salts (6321 ppm). 229 Tb.is species is primarily diploid and hybridizes with the tetraploid !• cuneata. The progeny, 2n=27, are fertile which suggests that!• cuneata ssp. introgressa mavrbe one of the parents of this tetraploid. (See Figs. 53-54 and 56-57) 2. Atriplex welshii. Hanson Erect shrub, 1.8 to 2.5 dm high, 4.3 to 4.5 dm wide, 3.9 to 4.1 dm in depth, much branched near the base, branches erect and layer only upon coverage of stems, strong tap- root present but lacks rootsprouts; leaves narrowly oblanceolate or linear, 19 to 30 mmlollJs', 3.5 to 4.5 mm wide, petiole not distinct from-blade but expressing itself to 1.3 to 2.6 mm, smaller leaves growing on short spurs in the axils of the larger leaves; flowering May and early June; fruiting bracts in clusters of 2 to 3 but oftentimes only one; pedicel minimal (0.2 to 0.8 mm); fruit 6.o to 7.8 mmlong, 4.2 to 5.6 mmwide, 2.8 to 4.8 in depth; heavily tuberculated (14-21 per plant) with the main apex 2.1 mmlong and 3 associated shoulders. Atriplex welshii, originally thought to be very restricted in distribution, occurs in small populations from 30 miles south of Wellington, Utah, to near Shiprook, New Mexico, and occupies clay soils low in soluble salts (less than 1600 ppm). It grows sympatrioally with!• corrpgata, !• ouneata, !• confertifolia, and !• obovata, but no putative hybrids were observed. The species appears to have cytological, morphological, and ecological similarities to!• cuneata ssp. introgressa. :Both grow in the Green River drainage area and occupy similar habitat types on mancos shale wastelands. Both are diploid species. Both appear to express similar growth habits and fruit types. They differ, however, in some of their morphological characteristics. Atriplex welshii has leaves which are keeled or involute, whereas!• cuneata ssp. introgressa lacks this trait. Atriplex welshii can also be 230 Fig. 52-53. Hbit of!• welshii ad habitat of A. cueata ssp. itrogessa. 52. !• welshii, 5 miles south of Cisco, Utah. 53. !• cuneata ssp. introgessa, 5 miles south of the Cabon-Eer County Line on Hwy U.S. 6-50. 231 54 tt•• ..... ,. ~~!t,ft'~•- ·-~~ ~., .. 4-~ \ ;~, ~i,_,~.~~ ·• .... .,.. • • • ... • ,. • .. ., \ t I 11 • • , • .;. 55 Fig. 54-55. Fuits of!• cueata ssp . introgessa ad!• welshii; each row represents the vaiation in a single plat . 54. !• cueata ssp.introgessa: Top. Wellington, Uta (2n=18). Bottom. Cabon-Tery Couty Line, Uta on Hwy U.S. 6-50 (2n=36). 55. !• welshii, 5 miles south of Cisco, Uta. Atriplex cuneata single plant population ssp. introgressa Carbon-Emery county line, Utah ~~f4 ?~. 1 mi. south of Wellington, Utah @;,~t!p& Atriplex welshii S mi. south of Cisco, Utah ~'1$~ S mi. south of Woodside, Utah I\) VI I\) Fig. 56. Fruit drawings of!• welshii and!• cuneata ssp. introgressa. Atriplex cuneata single plant population ssp. introgressa .. ----.::::::--.. Carbon- Emery county line, Utah ~···3~ 1 mi. south of Wellington, Utah Atriplex welshii E-··3 .. 5 mi. south of Cisco, Utah ....-- '------.::::::.9~·-··-··~~ -· -···· '- -····~ ---- 5 mi. south of Woodside, - Utah - -- ·····~···········-···?' # N \>I \>I Fig. 57. Leaf drawings of!• welshii and!• cunea.ta ssp. introgressa. 234 characterized as having a shorter and na.-rrower fruit beak (2.1 by 0.9 mm) which usually has at its base several shoulders and a minimal expression of a fruit stalk (0.5 mm), whereas, !• cuneata ssp. introgressa has a longer and wider fruit beak (3.1 by 1.8 mm) with relatively few side shoulders at the base of the beak and a very prominent pedicel (2.5 nunaverage). (See Figs. 52-57) 3. Atriplex falcata. (Jones) Standl. Erect shrub, 1.4 to 3.1 dm high, 1.4 to;.; dm wide, 1.5 to 3.5 elm in depth, suffrutescent at the base and much branched, rootsprouts extensively but not observed to 18'Yer; leaves narrowly spatulate to linear, 17 to 42 mm long, 2.8 to 6.8 mmwide, sessile or subsessile with petiole ranging from 1.0 to 1.6 mm; flowering in~ and early June; fruiting bracts fusiform and subsessile or some of them on slender pedicels (usually less than 3 mm); fruit ;.6 to 4.0 mmlong, 2.1 to 2.3 mmwide, 1.5 to 1.7 mmin depth; expressing several to many echinate spines (3 to 10 per bract) with one distinct apex (1.0 to 1.6 mm. Atriplex falcata, a species which stands out distinctly over most of its area, is characterized in the early spring and late summer by a yellow-green color. In the spring, it is associated with an a.nnua.l yellow mustard, whereas in late summer, its yellow fruiting stocks are conspicuous against the dark green vegetation of Ha.log,ton glomerata. The larger ephemeral leaves fall prior to seed dispersal and thus give the yellowish color. It usually forms almost pure stands in isolated pockets which are usually surrounded by Artemisia tridentata, Ceratoides lanata, or in the transition belt between Artemisia tridentata and Atriplex confertifolia. These neighboring species are almost completely excluded from the!• falcata patches. It appears that!• falcata 235 can competitively invade and slowly replace these associated species, most likely by the use of allelopatby. The strong leachate extracted from the fruiting bracts also suggests such a chemical inhibition to its neighboring species. Atriplex falcata grows in well drained soils, usually loamy in nature and low in soluble salts (usually less than 700 ppm). (See Figs. 58-62) 4. Atriplex tridentata. Kuntze. Erect shrub, 2.1 to 6.4 dm high, 4.5 to 5.3 dm wide, 4.1 to a.7 dm in depth, suffrutescent and much branched near the base; rootsprouts extensively and layers only when erect stems are covered; leaves linear-oblong, 22.7 to 27.3 mmlong, 3.7 to 5.5 mmwide, sessile or short petiolate (o.a to 1.5 mm), often with fascicles of smaller leaves in the axils of the larger leaves; flowering in late June and July; fruiting bracts triangular cuneate, compressed; fruit 4.2 to 5.7 mmlong, 3.0 to 4.3 mmwide, 1.5 to 2.2 mm in depth, usually 3-toothed apex with the center tooth the longest (1.1 to 1.9 mmapex), rarely pedicellate (0.1 to 0.2 mm), sides not appendaged (usually less than 4 tubercules). Atriplex tridentata is restricted basically to clay and clay loam soils of the old :Bonneville Lake bed. It appears to be the most salt tolerant of the Atriplex species. The range of soluble salts found in the soils is from 605 to 87,131 ppm, although most soils exceed 20,000 ppm. There appears to be a correlation between salt concentration and morphological expressions. Such plasticity could possibly account for the great diversity present in the species; this may be why separate popu- lations could be distinguished by plant height, plant depth, leaf length, and leaf width. Several distinct forms have been noted in this species. The typical erect habit is most prevalent. However, prostrate 236 ...._ --~--~ - Fig. 58-59. Hbitat of A. falcata. Te distinct population paaeters depicting the small isolated pockets of plbts ae evident. 58. 1 mile west of Re Patch Reseroir, Nevada. 59. 8 miles west of Mud Lke, Idao. Atriplex f alcata single plant population 3 mi. east of Sand Dune turnoff Jer.icho, Utah .. ~A ti-tl,h~ Desert Mtns., Utah &~. 8 mi. -•• of Mud lake, Idaho {j /!:J $ I\) VJ -.:i Fig. 60. Fruit drawings of!• falcata. Atriplex falcata single plant population 3 mi. east of Sand Dune turnoff, Jericho, Utah Desert Mtns., Utah Q 8 mi. west of Mud lake, Idaho w I\) \>I Fig. 61. Leaf drawings of!• falcata. 0:> 239 � • ' b ' � ♦ ), ♦ • 4 .. i • • 0 • � � • t, � 4) � ,> • 41 '> ' • 4 ' • ' • • • - � � ' ' ' + 1 ,. � .. � • 6 '> • • b t, • • • • ' • t . � • • • • • • • • ,is 'ti • • • • • • • • • ' w - - ♦ ♦ -- . - ; ; 1 ' • t ' t ' • i ' j i t ' ' .. 4 .. • t • • • • t •• ..,_ • • • • • • 1 • ------�·-· .- Fig. 62-63. Fits of!• falcata ad A. tridentata; each row represents the vaiation in a single plat7 62. A. falcata, 8.2 miles west of Jericho, Uta. 63. !• tridentata, 4 miles west of Ehaim, Uta. 240 forms have been observed in a number of locations. This low growing fonn appears to be mostly a vegetative stage and is correlated with extensive rootsprouting. It is possible that during heavy grazing or dry periods this form would predominate, but during ideal conditions, the typical form would occur. Atriplex tridentata is the only hexaploid in this study. It appears to be genetically distinct, even though it grows sympatrically with!• confertifolia, !• cuneata (2n=36), and!• cuneata ssp. introgressa. Only!• canescens is known to hybridize with!• tridentata, and the putative hybrids are 2n=45. (See Figs. 63-67) 5. Atriplex corrugata. Wats. Much branched shrub, forming mats o.6 to 1.3 dm high, 2.7 to 4.6 d.m wide, 2.8 to 5.4 d.m in depth; older branches spreading, younger flowering ones ascending, soft whitish-gray wood throughout; branches rooting down when in contact with the soil; leaves linear- oblanceolate or oblong, 7.4 to a.3 mmlong, 1.9 to 2.3 mmwide, appearing in crowded rosettes, petiole highly reduced (0.3 to o.6 mm);flowering late April and May; fruiting bracts sessile (0.4 too.a mmpedicel), narrowly-fan-shaped; fruit 3.3 to 3.6 mmlong, 2.1 to 2.8 mmwide, 1.1 to 2.0 mm in depth, the terminal free portion very broad and obtuse (0.9 to 1.7 mmin length and 1.9 to 3.0 mmin width); short stout tuber- cules on the basal sides (usually 8 to 12 tubercules per plant). Atriplex corrugata is restricted in distribution to cla:y and silty loam soils in southeastern Utah and western Colorado. It appears to tolerate a considerable amount of salt, growing in soils which range in salts from 244 to 12,221 ppm with most populations growing in soils containing less than 3,000 ppm. Like!_. tridentata, !• corrugata appears to respond to certain 241 Fig. 64-65. Hbit ad habitat of!• tridentata. Both illustrations taen from 15 miles south of Fish Springs, Uta. Atriplex tridentata single plant population 4 mi. west of Ephraim, Utah 0 \of CJ&~~~ 15 mi. south of Fish Springs, Utah J & e 1.5 mi. south of Sigurd, Utah & 8 ® I\J t Fig. 66. Fruit drawings of!• tridentata. Atriplex tridentata single plant population 4 mi. west of Ephraim, Utah 15 mi. south of Fish Springs, Utah 6 P 0 © 1.5 mi. south of Sigurd, Utah I\) -+"- Fig. 67. Leaf drawings of A. tridentata. \>I 244 environmental influences, such as water. The season of 1973 produced extensive plant growth due to a significant increase in precipitation. The plants and leaves were 5- to 10-fold more elongated than normal. However, clones which were tested in different soil types in the greenhouse failed to respond to water differences. Atriplex cor;rugata grows sympatrically with!• conferti- folia, .!• canescens, !• cuneata ssp. introgressa, !• cuneata (2n=36), !• welshii, and!• tridentata. Putative hybrids have only been observed with,!. confertifolia and!• cuneata. (See Figs. 68-71) 6. Atriplex gardneri. (Moq) Dietr. Shrub ascending, much branched near the base; roots down when covered to form mounds; tendencies toward becoming woody in some populations; 1.6 to 3.8 dm high, 4.4 to 12.3 dm wide, 4.1 to 14.8 dm in depth; leaves obovate to oblanceolate oblong, 17.3 to 42.7 mmlong, 7.1 to 11.8 mmwide, petiole poorly developed but present (2.1 to 7.0 mm); flowering late May and early June; fruiting bracts broadly cuneate or oblong; fruit 4.2 to 6.0 mm long, 2.6 to 4.0 mmwide, 1.5 to 2.5 mmin depth, pedicel minimal (0.8 to 1.2 mm) usually 2 to 6 toothed at the apex with the middle tooth being the longest (1.0 to 1.4 mmapex); surfaces of bracts generally smooth or lightly covered with echinate tubercules (3 to 12). Atriplex gardneri is a low-branching shrub distributed throughout Wyoming, Montana, and much of Canada. Like!• tridentata, it expresses a wide range of morphological variation. Most plants layer, forming a mound. However, in grassy areas, soil washing is minimal and the plants fail to layer. In most areas, there are plants that are completely decumbent, whereas others have many ascending branches. It appears that much of the 245 Fig. 68-69. Hbit ad habitat of!• corata. 68. 9.6 miles east of Blue Mountain, Colorado. 69. 5 miles southwest of Cisco, Uta. Atriplex corrugata single plant population 5 mi. south of Cisco, Utah $ fi7 a fJ (j e 8 mi. northeast of Vernal, Utah e t e e S mi. -south of Cisco, Utah w w w 8 mi. northeast of Vernal, Utah Q Q © w © I\:> i .i::,.. O'\ Fig. 70. Fruit and leaf drawings of!• corrugata. 247 (t 1-/1 ,. ' ff. fl: (, •!'t . t " •• r, r r: Ii' f . I. --� I·, " � • 1 � 1 f •�t • ·� 1''. t-11/r ♦ .. � • ♦ • • - ¥ iS � �. • t,. * �- �" � f;l ,Jf 0"" 0-1',1� �}·�· . ·�' •t•••��� � � � � 1 � � • ' � ♦ ,. � � -1� ,:I ' � .;: i� • ' � '" � if q • � � , • -t 11 t lj 1· '1 1t.,. Fig. 71-73. Fruits of!• corata, !• gadneri, ad!• cueata; each row represents the vaiation in a single plat. 71. !• corata, Ferron; Utah. 72. !• gadneri, Rck Springs, Woming. 73. !• cueata, Thompson, Uta. 248 variation is correlated with variation in amounts of water rather than salt. Even though the soluble salt ranges from 139 to 26,672 ppm, most of the populations grow in soils less than 1500 ppm. In most populations, only certain portions of the plants flower; the remaining plant parts continue to grow in tight rosettes. This is especially conspicuous in run-off areas such as along roadsides and washways where only the more heavily watered parts of a plant flower. One interesting variant observed and also reported by Hall and Clements (1923) is the somewhat upright, woody form from several locations in Wyoming (namely, Rock Springs and north of Lovell). The plants a.re about 5 decimeters high and are scattered among the usual form of!• gardneri with which they intergrade. It is possible that this form is a result of interspecific hybridization of.!• canescens and !• gardneri. The taxonomy of this northern species is still not completely resolved. Although the habit and leaf structures differ considerably from!• tridentata, the fruiting bracts so nearly parallel!• tridentata that it is difficult to distinguish to which species some plants belong. Also, much of the Canadian Atriplex appears to be distinct from that of Wyomingand Montana. It appears that the populations labeled!• buxifolia by Hanson are, in fact,!• gardneri. The error may have been made because Hanson was unable to observe any living specimens of!• buxifolia. Nevertheless, additional studies are needed for complete 249 understanding of the variation in this species. (See Figs. 72 and 74-78) 7. Atriplex cuneata. A. Nelson. Decumbent, decidedly woody shrub; 1.8 to 2.5 dm high, 5.8 to 9.7 dm wide, 6.4 to 10.0 dm in depth; stems erect, much branched at base, rootsprouting rare but layers when stems contact ground; leaves cuneate, blue- green in color, 14.5 to 18.3 mmlong, 8.5 to 9.9 mmwide, leaf base narrowing to a petiole 2.4 to 2.9 mmin length; flowering mid April and~; fruiting bracts globoid in outline with a short pedicel (0.9 to 2.5 mm); fruit 4.3 to 6.3 mmlong, 3.5 to 4.6 mmwide, 2.9 to 3.8 mmin depth, irregularly toothed at apex but usually expressing the center apex to 2.4 mm, heavily tuberculated (17 to 19 tubercules per fruit). Like Atriplex gardneri and!• tridentata, Atriplex cuneata is very polymorphic. The habit varies with variations in the habitat. In flood plains where the older stems are continually being covered, the plants form mounds, and the stems are of soft wood, whereas in grassy areas, the plants show considerable woodiness. This characteristic is very similar to that found in!• ga.rdneri. Atriplex cuneata is confined primarily to the mancos shales of southern Utah, western Colorado, northwestern New Mexico, and northeastern Arizona. These loamy and clay soils, usually containing less than 4,000 ppm salt, range from 244 to 20,558 ppm soluble salts. Here it commonly grows sympatrically with!• welshii, !• canescens, !.• obovata, !.• corrue;ata, and.!• confertifolia. It produces fertile hybrids with every perennial Atriplex with which it is 250 _, ,.- •( j 74 ( ,-✓ ,, .r ( Fig. 74-76. Hbit ad habitat of A. gadneri. 74. 18 miles north of Rwlins, Woming. 75. 3 miles east of Rock Springs, Womng (shows only pat of the plat as upright ad in flower ad the remaining portion maintaining the characteristic mat-like habit). 76. 1 mile east of Red Dsert, Woming. Atriplex gardneri single plant population 30 mi. north of laHs, Wyoming -047~~ 1 mi. east of Reel Desert, Wyoming t,J ()1~4~ 8 mi. east of Medicine Bow, Wyoming GOQB 0 t9 l1)ij 30 mi. north of Rawlins, Wyoming 15 mi. west of Casper, Wyoming 0 9\)0~ 4 mi. east of Blue Mtn., Colorado {9 0 e, I'\) VI ...a. Fig. 77. F.ruit drawings of!• ~eri~• 252 8 i 1 8. - • lz.i,-~ ·c .:- .. I' ; ! ! &• ·- 'E •I ,. l 8, ii .. '1 , 0 '1 0 ..t -= 0 I C Ja. tl • .,:I l0 ..: ·- I ·-.. E o •iif < • V -• !J ~- 253 sympatric, with the exception of!• welshii and!• obovata. (See Figs. 73 and 83-86) 8. Atriplex cuneata. Nelson. (2n=18) Shrub erect, 3.1 to 3.6 elm high, 5.a to 6.1 elm wide, 5.6 to 6.0 elm in depth, much branched near the base; plants becoming woody and seldom layering; leaves ovate or rounded ovate, 3.1 to 3.9 mmlong, 15 to 24 mmwide, petiole distinct (7.9 to 8.4 mm), leaves yellow-green in color; fruiting bracts subsessile, pedicel 2.2 to 2.5 mm in length; fruit 5.1 to 5.2 mmin length, 5.0 to 5.6 mm in width, 2.9 to 3.6 mmin depth; the apex triangula.r- subulate (1.2 mmlong and 0.25 mmwide, heavily . tuberculated (12 to 15 tubercules per fruit). This diploid is quite distinct from the tetraploid -A. cunea.ta., growing extensively on talus slopes in the northeast corner of Utah. Like the other diploids, it occupies soils low in soluble salts. Its large, rounded ovate leaves, which a.re yellow- green in color, and woody upright habit clearly distinguish it from the more widely distributed tetraploid. The habit, leaf coloration, and habitat a.re quite similar to the woody diploid, !• prretti. (See Figs. 79-82) Discussion The taxonomic significance of autopolyploids has often been a good subject for debate. Are they isolated enough to be considered different entities or a.re they still pa.rt of the original unit? Love (1960) and Lewis (1967) suggest that species status is achieved when there is a difference in chromosome number. They believe that genetic separation and ecological isolation are usually established by polyploidy and that new species formation has therefore occurred. If this is true, then the biological 254 Fig. 79-81. Hbit ad habitat of!• cuneata (2n=18) from nea Bonaza, Utah. 79 ad 80. 3 miles south of Bonaza, Utah. 81. 18 miles south of Bonaza, Utah. Atriplex cuneata single plant population 16 mi. south of Bonanza, Utah ;JJJ;~i}~ 3 mi. south of Bonanza, Utah ¢1/jl(J~ f} '1-$ 16 mi. south of Bonanza, Utah 3 mi. south of Bonanza, Utah 1 u 'l v Y N V, V, Fig. 82. Fruit and leaf drawings of!• ouneata (2n=18). 256 Fig. 83-84. Hbit ad habitat of!• cuneata. 83. West of Cisco, Utah (femle plat). 84. 5 miles south of Eer, Utah. Atriplex cuneata single plant population S mi. West of Cisco, Utah IS mi. East of Moab, Utah ~o,Q, OtJ®\t/4 3 mi. North of Price, Utah JQ{r~ ~itft~~ 3 mi. East of Thompson, Utah -0t~t~ S mi. South of Emery, Utah @~ I\) \J1 -.J Fig. 85. Fruit drawings of!• cuneata (2n=36). Atriplex cuneata single plant population . : .' ; j i. ~': . ' i ! I . ! ~· \ S mi. South of Emery, Utah CD(D ~ 3 mi East of Thompson, Utah (DQ) Q 0 3 mi. North of Price, Utah 0 0 I\) U1 JS mi. East of Moab, Utah $ 0 Q (X) Fig. 86. Leaf drawings of!• cuneata (2n=36). 259 species conc~pt, based upon interfertility, necessitates the division of the complex into morphological parallel species, each at a different chromosome level. However, recent workers have shown that gene flow does occasionally occur from diploid taxa to their sibling polyploids, and in some instances, the two cytological levels cannot be satisfactorily separated morphologically. Such has been reported in the following: Zea, Galilllll, Campanula, Patura, Secale (Woodell and Valentine, 1961); Achillea (Ehrendorfer, 1959); Sola.num (Marks, 1966); Primula (Naga.ha.ru.a.nd Hirotoshi, 1950); Dactylis (Carrol and Borrill, 1965). Thus, the original premise of Love a.nd Lewis is not universally applicable. In this study!• cuneata (2n=18) is the only diploid that can be distinguished morphologically from its tetraploid, which may suggest an allopolyploid rather than an autopolyploid origin. The results of this study clearly indicate that nomenclature revision is needed for two of the diploid entities. Atriplex cuneata ssp. introgressa is a diploid and not a derivative of intro- gressive hybridization and should be renamed. The unique broad.leaf diploid which was probably involved in the origin of the tetraploid !• cuneata, has not previously been defined taxonomically or reported. CHAP11ERVIII CONCLUSION Species within the Atriplex ga.rdneri complex appear to be highly adaptive to the dry saline soils of the Intermountain Deserts. Several factors, including plasticity in response to environmental alterations, heritable morphologicEf-1adaptations to harsh environ- ments, and ecological advantages of polyploid races over diploid ancestors, a.re probably responsible -for their remarkable success in these harsh environments. Probably the greatest limiting factor to saltbush distri- bution on most sites is their inability to withstand strong competition from other more aggressive species (McLean, 1953). The attending harsh environmental conditions in which they grow certainly appear to reduce the number of competitive species. Most populations show about 15 percent ground cover for Atriplex species, with £orbs and grasses averaging only 2 to 3 percent. The remaining 82 percent of the habitat is bare ground. Generally speaking, precipitation is probably the most limiting physical factor. Not only is the rainfall meager in areas where these shrubs grow, but also the distribution is uncertain and the evaporation rate relatively high. In fact, the high evaporation rate probably creates another problem in causing the accumulation of salt deposits on soil surfaces. 260 261 The thickness of leaves is often modified by the presence of salt (Chapman, 1960). Mendoza (1971) found in Atriplex hastata L. that with increasing NaCl concentrations, leaves a.re thicker and smaller in size. Flowers (1934) and Flowers and Evans (1966} found that.!• hastata growing in saline areas seldom reached the height of 70 cm and exhibited smaller leaves and shortened internodes, but in wetter, less saline areas, these same plants grow more than a meter high and have much larger leaves. The difference between these two forms is so striking that they were once thought to be two separate species. Such a response to environmental factors is not uncommonin this subshrub complex. For example, in wetter, less saline areas!• tridentata plants reach 91 cm in height; on drier, more saline contiguous areas the plants are often only 32 cm in height (data averaged from populations 8 miles west of Desert Mt., Utah, and 1.5 miles south of Sigurd, Utah). Black (1954) has drawn attention to the specialized nature of the leaf in Atriplex species. The characteristic "Kranz" type leaf anatomy associated with the c pathway, the thickened cell walls 4 and sunken stomata, the presence of an exterior, protective vesicular layer, and the possible capacity to absorb atmospheric water in humid periods, are all characteristics considered to favor drought resistance. The c dicarboxylic acid pathway is characterized by the 4 incorporation of into 4-Carbon acids, forming oxaloacetate, co2 malate, or aspartate. It has been observed that plants are c4 generally associated with high light and high temperature of arid 262 environments and are considered to be two- to three-fold more efficient in the assimilation of co2 than conventional Calvin cycle plants (Osmond, 1969). Osmond also reported that characteristics of the kinetics of carbon assimilation associated with these Atriplex species may be advantageous in water-use efficiency. Leaves of most Atriplex species are covered with bladders on both surfaces (Black, 1954; Troughton and Card, 1974) as well as wax plates. Chapman (1964) stated that the hairs are for water storage and hence are 06 advantage to plants growing in saline areas where they are said to be subjected to physiological drought. 1I1his suggestion seems unlikely, however, since the hairs contain liquid when the plant is young and actively growing, but when the plant is older and more likely to be able to store water, the hairs become deflated (Chapman, 1964). Jones (1971) extracted the liquid in the hairs of annual Atriplex and found them to contain relatively high concentrations of chloride ions. It is possible that the hairs are involved in chloride control rather than with water storage. Nevertheless, Walter (1954) maintains that halophytes need a certain amount of salt for development, and accumulate large amounts of chloride in their cell sap. It has been proposed by Pallaghy (1970) and West (1970) that the bladder hairs are used as a storage area for chloride ions. As the leaf accumulates chloride ions as a result of transpiration, the excess ions are actively transported into bladder hairs. Evidence for this type of mechanism for salt tolerance rests solely on the observation that the ion concentrations in the bladders are 263 considerably higher than that in the rest of the leaf tissue and that the ion content of the bladders represents about half of the total salt of the leaf (Pallaghy, 1970). This presmnably protects the delicate leaf tissue from excessive chloride ion concentrations and would thus allow for more normal functioning of leaf tissues. The presence of high chloride ion concentrations in the bladder cells thus appears to be another evolutionary adaptive trait. In addition, sodium chloride has a uniformly high reflectivity throughout the visible and the near infra.red region {Forsythe, 1969). Mooney, et al. (1974) postulated that in hydrated leaves, the salts in the glands a.re in solution. As the summer drought progresses, the leaves become increasingly more desiccated, and the salts crys- tallize. The drier the leaf, the more salt that would be crystallized and the greater the reflectivity, thus assisting in water conser- vation • .Another possible form of water conservation has been reported in Atriplex leaves by Wood (1962) and Arentsen (1972). They have shown that many species of Atriplex have the ability to absorb water directly into their leaves from atmospheres having as low as 36 percent saturation. Most Atriplex species a.re remarkably resistant to drought, not only because of their leaf adaptations, but also because of their deep tap-root and numerous lateral roots. It has been established that under dry conditions plants develop relatively more roots than shoots (Oppenheimer, 1960; :Brey, 1963). This characteristic was observed in the field in Atriplex when young 264 plants of undetermined age, only one-half inch high, had roots which extended six to ten inches into the ground (also observed by McLean, 1953). On a comparative basis, then, the roots of Atriplex apparently elongate at a faster rate than the roots of mesophytes. Jones (1969) reported root extension rates of!• nummularia and!• vesicaria to be e.7 cm/da;y. If the Atriplex species in the!• g;ardneri complex are comparable with these Australian species, then some of their competitive nature must, in part, be attributed to their rapid root growth. It should be noted here, however, that McLean (1970) suggested that Atriplex species were poor competitors because of their slow root growth. Field observations suggest that early in the life of a seedling one main root usually develops with a strong tendency for vertical growth. McLean (1953) excavated the roots of one plant of !• nuttallii to the depth of seven feet. At the seven foot level there was little lessening of the root diameter from that of the three foot depth. Since Atriplex is drought tolerant, it supports the suggestion of :Branson, et al. (1967) that deep-rooted plants can endure considerable drought. In addition to a main tap-root, fine shallow roots are usually developed in abundance at depths below 10 cm. The ephemeral nature of these roots may be an adaptation for opportunity growth in relation to rainfall and nutrients. Roots in Atriplex may also play an important role in plant propagation. Live lateral roots ofttimes join plants together. Young shoots or suckers usually develop from these interconnecting roots. After the new shoots become 265 established with their own root system, the parent root usually dies and the dec~ing connections are ofttimes removed by termites. Since sterility due to polyploidy, insect in£estation, and germination inhibitors all tend to reduce the number of sexual progeny in certain species, rootsprouting may be a ve:ry important safeguard for survival. To some extent, Atriplex species may be adaptive over a wide variety of environmental conditions • .An interbreeding population, through selection of adaptive individuals and from sexual gene exchange may set up a self-perpetuating system in which new functioning individuals are continually being produced as old ones die out. Ou.t of the mass of seed produced, the environment permits survival of only those which are capable of car:rying out all of their essential functions under prevailing conditions. It is conceivable that a species could spread over a large distance without showing a:ny genetic divergence. If its range of tolerance were fairly wide and if it were also to migrate into habitats ve:ry similar throughout its entire range, then there may be no selection for diversity. In nature this probably seldom happens. However, Good (1931) cited an example in Juglans nigra in which apparently similar plants show different temperature tolerances in different parts of their range. Also, genetic differences in Potentilla gla.ndulosa were shown by Clausen, et al. (1947) to arise because plant migration, however slight or however gradual, continually bring plants into slightly different conditions where selection identifies a:ny slight genetic differences which 266 adapt these plants more closely to the new conditions. How the diversity becomes fixed will be dependent on the breeding systems of the plants. Self-fertilized species ordinarily develop rather uniform species but outbreeding plants, such as Atriplex, should result in a continuous cline in most instances. For any major evolutionary advance to take place, a species with a high degree of genetic variability must be exposed to a rapidly changing environment which offers new ecological niches to which new plant types can become adapted. Genetic recombination ordinarily is the major source of such variability, so that the evolutionary lines most likely to take advantage of a changing environment are those in which recombination is raised to a maximum. Although the short term effectiveness of hybridization and subsequent segregation is limited by hybrid sterility and other effects of recombining the factors which contribute to reproductive isolation, these limitations can in many instances be tolerated by "fixed hybrid vigor" and a partial restoration of fertility accompanying polyploidy. A number of factors appear to favor polyploidy in Atriplex. The fact that many are herbaceous perennials and have an efficient means of vegetative reproduction makes them well equipped to take advantage of a wide range of environmental conditions. As Stebbins (1956} and Jones (1961) have pointed out, the ecological tolerance of polyploids formed from differing physiological races may be greater than the sum of the tolerance of the two contributing entities. 267 The important role of hybridization in the origin of successful polyploid races is widely accepted {Stebbins, 1950; Davis and Heywood, 1963). Even within autopolyploid complexes intervarietal polyploids are more prevalent than autoploids derived from the doubling of the chromosome number of non-hybrid individuals (Stebbins, 1950). The advantage of "hybrid polyploids" over strict autoploids or their diploid progenitors is due to their greater adaptability; a wider ecological tolerance results from recombination of the parental genotypes which are either adapted to different habitats in the same population or which have different modes of adaptation to the same habitat (Stebbins, 1956). Polyploids originating in this manner are physiologically better equipped to colonize newly available sites (Reese, 1961). Reese suggested that because of this adaptability, a higher proportion of polyploids than diploids occupies a.reas uncovered by pleistocene glacial recession, accounting for the south to north increase in the relative frequency of polyploid species. There is abundant evidence that the dioecious shrubs of the genus Atriplex had their origin far to the south, probably in Mexico (Hall and Clements, 1923). Their migration to the north and northwest most likely followed the glacial retreat. Probably with adaptation to arid saline valleys of Mexico, came the accumula- tion of salts in the plant tissues. This salt, acting as an "antifreeze" system, may have given the plants a tolerance to cold and cooler climates. Thus, the stabilization and segregation of this complex most probably closely followed the melting of the last glacial 268 substage which, according to Prest (1957), occurred approximately 7 to 10 thousand years ago. Hagerup (1932) has suggested that polyploids are more tolerant of extreme ecological conditions than their diploid relatives. Tischler (1937) and Wulff (1943) found a high percentage (65 percent) of polyploids in the balophytic flora of certain islands in the North Sea, and from that concluded that polyploidy is associated with adaptation to the severe conditions of saline habitats. Such appears to be the case. Presumably, diploid progenitors moved northward along the more mesic habitats which were relatively low in soluble salts. In their movement, they left pockets of diploids behind which, upon isolation, yielded the differences observed to~ in these species. If at the time when they produced the polyploid derivatives, diploid species still possessed a wealth of ecotypes adapted to different environments, the diploids and probably also the polyploids, expanded their distribution areas as new habitats became available. The difference in geographic distribution between diploids and polyploids would nevertheless have been maintained even under those conditions, because of the tendency of the tetraploids to occupy different new habitats from those taken over by the diploids. After the develop- ment of tetraploid races as discussed above, their migration may have followed the newly exposed arid valley systems. Such a migration would represent an example of adaptation through the development of a derived polyploid species adjacent to the xeric habitats of the diploid progenitor as discussed by Stebbins (1950). 269 The diploid populations in this complex have much in common. They all occupy soils low in salt, and usually, although not always, grow in the better drained soils. These diploid populations have not as yet been found in vast acreages but instead occupy small isolated pockets throughout the west. The diploids have a great deal of morphological similarity to their tetraploids and in most cases a.re indistinguishable from them. The diploids which have easily recognized tetraploids include!• falcata, !• gardneri, and !• cuneata asp. intro,sressa. The diploid form of!• cuneata has fruit characters that are very similar to the tetraploid but differs greatly in its leaf characters, thus making it easily distinguishable from its tetraploid. The tetraploids generally grow in the lower valley floors which are characteriz'3d by heavy soils of high salt and sodium content and generally lacking in available water. Though polyploidy is commonin the!• gardneri complex, the type of ploidy present and the origin of that ploidy are certainly not completely resolved. However, the recurring theme of morpho- logically similar diploids and tetraploids strongly suggests autopolyploidy as a possible origin of some of the species. The diploid progenitors of tetraploid and hexaploid species a.re most likely !• falcata, !• welshii, !• gardneri, !• cuneata, and!• cuneata sap. introgressa, with the following possible ancestries: 1. Atriplex cuneata (2n=36) most likely involved the introgressive hybridization of -A. cuneata and -A. cuneata asp. 270 introgressa. The morphological expressions appear intermediate between the two. 2. Atriplex corrµgata (2n-36) JDB¥have come from a stock similar to the newly discovered diploid in Mexico by H. c. Stutz, labeled!• saltilloensis. 3. Atriplex e;argneri (2n•36) appears morphologically inseparable from the diploid, and thus autopolyploidy or intra- specific allopolyploidy is suspected in their origin. 4. Atriplex tridentata (2n-54) most likely evolved from a diploid source similar to the late flowering -A. welshii populations north of Woodside, Utah. Since tetraploid populations were observed, backcrossing onto the diploids could easily give rise to a highly adaptive hexaploid upon doubling of the chromosomes.· It appears that this species developed about the same time as the draining of Lake Bonneville (12,000 years ago according to Bissell, 1968), because its distribution is primarily restricted to the old lake bed. LIST OF REFERENCES Arentsen, J. 1972. Absorcion foliar de humedad atmosferica y relaciones hidricas en Atriplex semibaccata !• ~. y Atriplex repanda Phil Tesis de grado para optar al titulo de Ingeniero Agronomo. Escuela de Agronomia de la Universidad de Chile. Santiago. 80 pp. Bassett, I. J. and c. w. Crompton. 1971. In IOPB Chromosome Number Reports XXXIV. Taxon 20:785-=f97. Beadle, F. c. W. 1952. Studies in Halopbytes. I. The germination of seeds and establishment of the seedling of five species of Atriplex in Australia. Ecol. 33:49-62. :Bissell, H.J. 1968. Bonneville-an ice-age la.lee. Geology Studies, Brigham Young University, Vol. 15(4):1-66. Bla.ok, R. F. 1954. The leaf anatomy of Australian members of the genus Atriplex. 1. Atriplex vesicaria Howard and!• mmmmlaria Lindl. Aust. J. Bot. 2:269. Bouyoucos, G. J. 1936. Directions for ma.king mechanical analysis of soils by the Hydrometer Method. Soil Science 42:225-230. Bouyoucos, G. J. 1951. A recalibration of the Hydrometer Method for making mechanical analysis of soils. Agron. J. 43:434- 438. Branson, F. A., R. F. Miller, and I. s. McQueen. 1967. Geographic distribution and factors affecting the distribution of salt desert shrubs in the United States. J. Range Mgt. 20(5): 287-296. :Bray, J. R. 1963. 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Lorenzo Pope Department of Botany and Range Science Ph.D. Degree, August 1976 ABSTHACT Growing on dry saline soils throughout the Intexmountain Region of the United States is a group of herbaceous, perennial species of Atriplex. including!• corrugata, !• cuneata, !• cuneata ssp. introgressa, !• falcata, !• gardneri, !• tridentata, and!• welshii, designated as the Atriplex gardneri complex. Highly adaptive and competitive in the arid salt deserts, these species are valuable as forage for livestock and wildlife. Because of extensive variation present within this complex, considerable taxonomic confusion has resulted. To clarify taxonomic and phylo- genetic relationships, selected populations and plants were analyzed morphologically, cytologically, ecologically, phenologically, and genetically. Polyploidy is common within most of the major taxons. The polyploid species show little morphological variation from that of their diploid ancestors. Diploids occupy well drained soils relatively low in salt and grow in isolated pockets; polyploid derivatives are more widely distributed, growing in the lower valley floors·characterized by hea:vy soils of high sodium content. - .