A SYSTEMATIC STUDY OF INDEHISCENT-FRUITED YUCCAS

IN THE CHIHUAHUAN DESERT

by

R. LAURIE ROBBINS, B.S. in ED., M.A., M.A.

A DISSERTATION

IN

BOTANY

Submitted to the Graduate Faculty of Texas Tech University in Partial Fulfillment of the Requirements for the Degree of

DOCTOR OF PHILOSOPHY

Approved

December, 1983 d,^ ,3 ACKNOWLEDGMENTS

I deeply appreciate the support of friends and family along the way. I am also indebted to Dr. David K. Northington for his direction on this project and to the members of my committee for their helpful criticism.

ii TABLE OF CONTENTS

ACKNOWLEDGMENTS ^^

ABSTRACT IV LIST OF TABLES VI LIST OF FIGURES Vll SECTIONS

I. INTRODUCTION 1

II. MATERIALS AND METHODS 5

III. RESULTS 10

Yucca baccata and If. endlichiana 10

Yucca camerosana and Y. faxoniana 14

Yucca decipiens and Y. filifera 19

Yucca torreyi and Y_. treculeana 22

IV. DISCUSSION 28

V. TAXONOMIC CONCLUSIONS 31

LITERATURE CITED 33

APPENDICES 35

1. Key to species 35

2. Taxonomic treatment 37

3. Collecting localities by species, country, state,

and county 49

4. Specimens examined from other herbaria 55

iii ABSTRACT

Plants of the genus Yucca (Family Agavaceae) are strictly of

New World distribution, occurring in the U.S., Mexico, and Central

America. Because of the great size of many members of the genus, and because of previous inaccessibility of much of their ranges until fairly recently, little has been done to evaluate the variabi­ lity within the group. With the exception of Trelease's (1902) work on the genus, other studies have been done strictly within the con­

fines of political boundaries. This is the first to deal with the

group within an ecological unit, namely, the Chihuahuan Desert.

Eight taxa of indehiscent-fruited yuccas occur wholly or in part in this area. Of these, six appear as "pairs" that closely

resemble each other and possess complimentary ranges (either north-

south or east-west). Data and voucher material consisting of gross plant morphology (measurements), flower, fruit, and leaf measurements,

and flavonoid patterns from greenhouse-grown seedlings were taken.

Analyses of these data provided the basis for evaluating not only the amount of variability present in each of the taxa, but to reevaluate the taxonomic alignment of the taxa, as well. It was

found that gross plant morphology and fruit morphology provide the most important characters for separating the taxa. Flowers are extremely conservative within the entire genus, but leaves are highly variable, even within a single taxon. The available data has lead to a realignment of the Y_. carnerosana-Y. faxoniana complex to more accurately reflect the probable species alignment, and a combination iv of two previously recognized species (Y_. torreyi and Y_. treculeana) into a single species (Y. treculeana), LIST OF TABLES

1. Classification of the Yucceae as per Trelease (1902) 53

2. Classification of the yuccas of the southwestern United States as per McKelvey (1938, 1947) 60

3. Classification of the yuccas of the southwestern United States as per Webber (1953) 62

4. Classification of the yuccas of Mexico as per Matuda and Pina L. (1980) 63

5. Measurements (in centimenters) and characters recorded on entire Yucca plants 65

6. Measurements (in millimeters) and determinations taken on

each of 10 flowers per Yucca plant 66

7. Measurements (in millimeters) taken from each Yucca fruit 68

8. Measurements (in millimeters) and characters taken from Yucca leaves 69 9. Means, ranges, and standard deviations for 12 morphological characters taken on indehiscent-fruited species of yuccas in the Chihuahuan Desert 70

10. Means, ranges, and standard deviations for flower measurements for species of indehiscent-fruited yuccas in the Chihuahuan Desert 72

11. Means, ranges, and standard deviations for fruit measurements for species of indehiscent-fruited yuccas in the Chihuahuan Desert 75

12. Means, ranges, and standard deviations for leaf measurements for species of indehiscent-fruited yuccas in the Chihuahuan Desert 76

vi LIST OF FIGURES

1. Collection localities, specimens examined, and distribution of "torreyi" (x), "treculeana" (triangles), "Cuatro Cienegas" (closed circles), "Del Rio" (open circles), and "Post" (+) populations used in this study 78

2. Collecting localities, specimens examined, and distribu­ tion of Y. decipiens (circles) and Y. filifera (x) used in this study 80

3. Collecting localities, specimens examined, and distribu­ tion of Y. carnerosana (open circles) and Y. faxoniana (closed circles) used in this study 82

4. Collecting localities, specimens examined, and distribu­ tion of ][. endlichiana (triangle) and Y_. baccata (closed circles) used in this study 84

5. Plot of Factor III against Factor I for whole plant data for Y. baccata (open circles) and Y. endlichiana (closed circles) populations . 86

6. Plot of Factor II against Factor I for fruit data on Y. baccata (open circles) and _Y. endlichiana (closed circles) populations 88

7. Plot of Factor II against Factor I for leaf data of Y, baccata (open circles) and Y. endlichiana (closed circles) populations 90

8. Plot of Factor III against Factor I for whole plant data for populations of Y_. carnerosana (open squares) and Y. faxoniana (closed circles). 92

9. Plot of Factor II against Factor I for flower data on populations of ][. carnerosana (open squares) and Y. faxoniana (closed circles) 94

10. Plot of Factor III against Factor I on leaf data for populations of Y. carnerosana (open squares) and Y. faxoniana (closed circles) 96

11. Plot of Factor II against Factor I of total plant data from populations of Y. filifera (closed circles) and Y. decipiens (open squares) 98

12. Plot of Factor II against Factor I for flower data on populations of Y. filifera (closed circles) and Y. decipiens (open squares). 100

vii 13. Plot of Factor II against Factor I on fruit data from populations of Y. filifera (closed circles) and Y. decipiens (open squares). 102

14. Plot of Factor II against Factor I for leaf data on populations of _Y. filifera (closed circles) and Y. decipiens (open squares) 104

15. Plot of Factor III against Factor I for total plant data for populations of "torreyi" (open circles), "treculeana" (closed circles), "Cuatro Cienegas" (closed triangles), and "Del Rio" (open diamonds) plants 10^

16. Plot of Factor II against Factor I for flower data of "torreyi" (closed triangles), "Post" (closed squares), "treculeana" (closed circles), "Del Rio" (open circles), and "Cuatro Cienegas" (open diamonds) populations 108

17. Plot of Factor II against Factor I on fruit data for "torreyi" (open circles), "treculeana" (closed circles), "Del Rio" (open diamonds), "Cuatro Cienegas" (closed triangles) populations of yuccas

viii A SYSTEMATIC STUDY OF THE INDEHISCENT-FRUITED YUCCAS IN

THE CHIHUAHUAN DESERT

I. INTRODUCTION

The genus Yucca is strictly of New World distribution, occurring throughout most of the United States, Mexico, and Central America.

Although traditionally placed in the Liliaceae, Hutchinson (1934) included it in the Agavaceae, a treatment followed here. PiKa L. (1980) recognizes 47 species in the genus. Within the group, nomenclatural puzzles have arisen as a result of several confounding factors.

Sargent (1895) summarized the situation rather succinctly in stating

"Yuccas are difficult plants for the botanist to manage owing to their size and nature; and it is almost impossible to preserve in herbaria specimens that adequately illustrate the species. Individuals of the same species vary widely in the length and width of their leaves and

in the size of their flowers and fruit, so that the seedlings of one plant scattered through the gardens of different countries, might be given different names by botanists familiar only with a few individuals.

.... It is not surprising, therefore, that there is hardly a group of garden-plants about which there is so much confusion in books, and this confusion will never be cleared up until the different species are studied extensively in the field, and then gathered in some

California or Mexican garden where their development under normal conditions can be patiently watched."

Engelmann (1873) was the first to monograph the group. His treatment, consisting of two subgenera and three sections under one of the subgenera, is regarded as valid today. What he (Engelmann, 1871) initially termed sections Sarcocarpa, Clistocarpa, and Chaenocarpa under the subgenus Euyucca, became Sarcoyucca, Clistoyucca, and

Chaenoyucca in his later publication (Engelmann, 1873). Within this classification scheme, he placed 14 naturally-occurring species.

Baker (1892) maintained this alignment but included only 11 species.

It was not until later, however, that Trelease (1902) provided the first major revision of the group and seriously addressed the problems that had arisen as a result of extensive plantings in Europe of materials originating in the New World. Descriptions of new species abound in European horticultural and botanical publications dating back to as early as 1597. Indeed, according to Trelease, one species of a Yucca from the South Carolina-Florida area had been in continuous cultivation in Europe since 1596 and, at the time of his writing, was represented by a considerable number of garden forms. Trelease (1902) took on the difficult task of clarifying the taxonomy to that time. At the same time, he attempted to resolve the taxonomy of what he regarded as "spontaneous" (or naturally-occurring) species in the United States,

Mexico, and Central America. Available to him were herbarium specimens

(including those obtained from the border surveys) and material from his own travels and collections. Travel in the arid, sparsely populated areas of northern Mexico and the southwestern United States at that time was difficult. When one views Trelease's accomplishments with the appropriate time frame in mind, one can appreciate the enormity of the task representing some 16 years of herbarium, field, and garden work that went into his 1902 treatise. Table 1 gives the classification as arranged by Trelease (1902) in that publication.

The next major work was done by McKelvey (1938; Table 2), and

Webber's (1953) treatment is shown in Table 3. Both authors dealt only with the Yucca in the southwestern United States. McKelvey's extensive treatment dealt with several remaining taxonomic problems that were not resolved by Trelease. The most recent taxonomic work is that by Matuda and Pina L. (1980) on the Mexican species of Yucca

(Table 4).

Although there has been a resurgence of interest in the genus with respect to economic importance (see for example the volume on Yucca compiled by the Centro de Investigacion en Quimica Aplicada, published

in 1980), especially in Mexico, relatively little else has been done

taxonomically with the genus.

My interest in Yucca initially was born of a difficulty in

readily distinguishing between two species from the trans-Pecos region

of west Texas. It was then expanded to a larger consideration of the

genus in view of the demonstrated variability within the species as

discussed by Robbins £t al. (1980). Although, as indicated in the

quote by Sargent (1895), variability in the group was early recognized

by some, it was not adequately assessed because of difficulty in

traveling to inaccessible places and because of low sample sizes. In

fact, variability was far overestimated by some workers to the extent

that several quite diverse groups were included in a single species.

For example. Yucca baccata of Engelmann (1873) consisted of a number of

varieties that now have been appropriately separated into specific

entities. Rather than choosing an area delimited by political boundaries, as had most of the previous authors, I chose an area defined instead by ecological boundaries (i-.^. , the confines of the Chihuahuan Desert, as per Johnston, 1979) in trying to understand the genus as a whole.

Within this area are found eight species of indehiscent- or fleshy-fruited yuccas (in McKelvey's 1938 section Sarcocarpa), six of which have their entire range within the area. These species are Yucca carnerosana, ][. faxoniana, Y. endlichiana, Y_. torreyi, Y. filifera, and

Y. decipiens. The remaining two, Y_. baccata and Y_. treculeana,have ranges that extend beyond the limits of the Chihuahuan Desert; Y. baccata is sparsely scattered throughout the southwestern United

States, and Y_. treculeana extends into the southeastern part of Texas and northeastern Mexico to the Gulf coast. After an initial examination an interesting pattern emerged; of the eight species, six could readily be placed into "species pairs" based on gross morphological characters.

Yucca torreyi and _Y. treculeana represent a pair with an east-west distribution, respectively, in the northern part of the desert (Fig. 1).

Y_. decipiens and _Y. filifera represent a similar east-west distribution, respectively, in the southern desert (Fig. 2). The third pair, Y. faxoniana and Y. carnerosana, are distributed in a north-south fashion, respectively, down the center of the desert for its full length (Fig.

3). Of the remaining two species, Y_. endlichiana possesses an extremely limited range in southern Coahuila, and Y. baccata barely reaches into the Chihuahuan Desert from a much more extensive range in the southwestern United States.

The purpose of this study was to conduct extensive field studies, observing the plants in their natural ranges, and to collect and analyze a substantial amount of data that would provide a more complete assessment of the extent and nature of the variability of these species of Yucca. I felt that until this kind of study was completed, it would be extremely difficult if not impossible to identify herbarium material with any measure of confidence. It should be noted that previous works have based taxonomic alignments on single or a few specimens or on herbarium materials, and, as Sargent (1895) noted, herbarium collections inadequately represent such large plants as yuccas. Therefore, the significance of large sample size in this work is that it provides a more solid basis for taxonomic alignments than was previously available.

II. MATERIALS AND METHODS

Field work to obtain materials for this study was done in 1975

(west Texas ]f. carnerosana and _Y. faxoniana) and from 1979-1983 (all eight taxa throughout the Chihuahuan Desert). Most collections were made during the spring and early summer of each year, but late-blooming dates for some of the species necessitated late summer-early autumn collections in order to obtain fruit.

Collections were made when possible in nearly all parts of the ranges of all eight species and consisted of a color slide of the plant, a leaf, and, depending upon the stage of reproduction, either

10 flowers or several fruits.

Figures 1-4 show collections plotted by species and by locality

(or population). Appendix 1 lists the collecting localities by species;

Appendix 2 lists specimens examined from other herbaria. When the

DODulation was extensive, a single collection was made of material fror. 6 at least 10 plants chosen at random. Other smaller, and often isolated populations were sampled as extensively as possible. Destruction of habitat and of yuccas and other associated vegetation for agricultural purposes is extensive in large areas of the range of the plants; hence, populations are often small, and with from only 20-40% of the plants normally reproductive during any single year, many populations are represented by small samples (see individual accounts for indication of sample size).

Two types of data were taken: quantitative (as direct or indirect measurements) and qualitative (character states). The latter were coded numerically and were treated as quantitative characters for statistical purposes.

Because direct measurements of the plant itself were difficult, and in at least four species virtually impossible owing to large size, color slides were taken with a clipboard of known size in the photograph to serve as a reference. When the slide was projected onto a screen, measurements were taken and, using the known clipboard dimensions, were converted to centimeters. Although the measurements obtained by this method are approximate, it was possible to obtain a considerable amount of information about general size, extent of branching, number of rosettes and reproductive rosettes, and general growth form. A total of 548 plants from 176 localities was photographed and measured (leaf and flowers or fruit also were taken). Table 5 lists the measurements and determinations that were obtained from each slide.

Flowers were taken at anthesis from near the center of the inflorescence, preserved in FAA, and measured in the laboratory. Table 6 provides a list of the measurements (in nmi) or determinations for each flower. Ten flowers were measured from each of 384 plants from 91 localities.

Fruits were taken when mature from near the center of the infructescence. Additional mature fruits served as a seed source for future work but primarily for the immediate purpose of raising seedlings for flavonoid analyses. Fruits for measurement and voucher purposes were split in half longitudinally and laid between sheets of newspaper in a plant press. No pressure was applied other than the weight of the overlying layers and the top press board. Fruits of some of the species are extremely loosely structured when fully ripe, and as such tend to spread out considerably when pressed. From the dried specimens, five seeds from near the center of the fruit were extracted and measured; seeds at the end of the six rows within the ovary are rounded on the side toward either end of the fruit (some approach being nearly round).

In the frequent event of the constriction of the fruit resulting from feeding and emergence of Tegeticula (yucca moth) larvae, seeds were taken from areas well away from these constrictions. Fruits from 374 plants from 119 localities were used in the analyses. Table 7 lists the measurements taken on each fruit (in mm).

A leaf collection was made from near the middle of the rosette of functional leaves (as close as possible to five positions up from the senescent leaves hanging down from the rosette); this was done to ensure that each leaf was fully mature and at a position equivalent to those taken from other plants in the same and in different populations.

All measurements were taken on pressed dried specimens (in mm) so that 8 herbarium material could be used for measurements as well. Leaves from

579 plants representing 235 localities were used in these analyses.

Table 8 is a list of the measurements and characters taken from each leaf.

Extra fruits and seeds were collected for later laboratory work.

Flavonoid analyses were conducted using air-dried leaves from greenhouse-grown seedlings. It has been noted by others working on similar plants (Agave; Northington and Burgess, pers. comm.) that flavonoid extractions from mature leaves are rendered much more difficult by the presence of tough fibers and thick cuticle. Before analyzing seedling leaves, extractions from mature and seedling leaves were run in identical circumstances, and it was found that both gave equivalent results. Dried leaf material was extracted with 85% methanol and spotted onto Whatman 3MM chromatographic paper (46 by 57 cm), as described by Mabry et alL. (1970). The sheets were then run in a descending chromatography cabinet in two dimensions; the first in TBA

(a 3:1:1 mixture of reagent-grade tertiary butyl alcohol:reagent-grade glacial acetic acid:distilled water), and the second in a 15% solution of reagent-grade glacial acetic acid in distilled water. Sheets were thoroughly dried between the two runs and at the completion of the second run. The sheets were then viewed with ultraviolet light.

Compounds were circled and the point of highest concentration of each compound was marked. The RF values were then calculated for each compound from this marked point. Application of ammonia vapor revealed the presence of no additional compounds. A master "finger­ print" map was then constructed for each species. A total of 712 sheets, representing 256 plants from 88 localities,were run and scored.

For comparative purposes, sheets from eight additional species of Yucca

(closely to distantly related and from areas within the Chihuahuan

Desert and from outside the desert) were run. Additionally, similar

sheets were run from two closely related genera (Manfreda and Hesperaloe)

in the Agavaceae.

Data derived from the five sources (entire plant, flowers, fruits,

leaves, and flavonoids) were then coded, scored, and manipulated using

an IBM 3033 computer available at Texas Tech University. Data

manipulation producing basic statistics was performed using SAS

(Statistical Analysis System, 1982 ed.).

Multivariate analyses were performed using two packages available

at Texas Tech. The NT-SYS package (Rohlf et^ al^. , 1980) was used to

perform cluster, factor, and principal components analyses using

means calculated by localities as OTU's (Operational Taxonomic Units).

Each of the five data sets was analyzed by species "pair." Although

Yucca baccata and Y. endlichiana do not closely resemble each other,

they were considered as a pair for purposes of analysis.

Specimens showing up in the plots produced by the NT-SYS factor

analysis program as obvious outliers were reexamined and the

identification was rechecked. Realignments of identification were made

when the specimen had clearly been misidentifled. In the case of the

Y. torreyi-Y. treculeana pair, the original species designations were

altered to reflect geographic groupings rather than the presently

accepted nomenclatural alignment. In the Y. carnerosana-Y. faxoniana

pair, the species also were realigned along geographic grounds prior 10 to rerunning the data.

Discriminant function analysis was then run on each data set for all species using the DISCRIM procedure in the SAS (1982) package to deremine if. given all the characters, the individuals were correctly classified into groups.

III. RESULTS

As iTientioned previously, the eight species under consideraticn in this paper are readily separable intc three species "pairs," the ccrpcnents of each pair closely resezibiing each other, plus tvc species

(Y\.ica b a c: a t a and Y. endlichiana) that are readily distinguishable

'IC'L':\ frcn each ether and frrn the ether taxa in the group. Because c::c u .he rrir.arv concerns cf this studv involved the facilitv with vhich one can distinguish betveen the two taxa of each pair, the

£n?.lvs£S vere dene species pair by species pair, data sec by data set, ar;C vi.ll be discussed as such. V. baccata and j^. enclichiana vere grcupec together for the analyses.

Tables 9-12 contain means, ranges, and standard deviations for all characters in the total plant, flower, fruit, and leaf data sets, resnectivelv. Values given in the following discussion are means unless cthervrise indicated.

• u c ca a baccata and Y. endlichian. Tnese two taxa are the most easily recognisable cf the eigh^ under censiderat ien, and their ranges within the Chihuahua?. Dese: are relatively snail. Y. baccata has a substantial range in the

southwestern Vnited States and nerthwesterr, Mexico but barely 11 extends into the northwestern portion of the Chihuahuan Desert (Fig. 4)

The species is thinly scattered, primarily in rocky areas at higher elevations (Wallen and Ludwig, 1978). Yucca baccata is characterized by wide leaves, generally large fruit, and a short caudex or decumbent stem.

The non-arborescent Y_. endlichiana, on the other hand, is one of the most "atypical" of the yuccas; the rosette is rather diffuse, the leaves are triangular in cross sections (rather than being thin and bladelike), the inflorescence is diffuse and lacks a central axis to which the panicle branches attach, and the flowers are maroon- and cream-colored (as opposed to being wholly cream-colored), and are found contained well within the leaves. Although clearly Yucca, the flowers are characteristic in being maroon-colored on the outside and cream- colored on the inner surface of the tepals and having either maroon- or cream-colored pistils. A faint maroon tinge in individuals in the

Y. torreyi-Y. treculeana group is the only coloration other than cream-colored that occurs in other members of the genus.

Yucca endlichiana is a small plant 135-539 cm (mean, 291 cm) high, whereas Y_. baccata is taller, 441-1193 cm (mean, 785 cm) (Table 9).

Both have a single rosette and both have the inflorescence completely enclosed within the rosette itself. Panicle shape in Y. endlichiana is diffuse, as the central axis is absent; _Y. baccata has an ovoid to elongate ovoid-shaped panicle on a central axis.

Factor analysis of the two species (using six populations of Y_. endlichiana and two of Y. baccata) showed that 96.8% of the variation was accounted for in the first three factors. Of primary importance 12 were height of the plant, shape of panicle, and height of inflorescence.

Loadings of these three characters were all positive: 0.942, 0.953, and 0.887, respectively, in the first dimension. These size and shape factors allow the two species to readily be separated, as shown on Fig.

5 (Factor III plotted against Factor I). The relatively high loading of height of panicle on Factor III (+0.643), however, is not sufficient

to separate the two species in that dimension.

Fruit data for eight populations of Y_. baccata and four of Y_.

endlichiana reveal similar size differences. Y. endlichiana has much

smaller fruit, averaging 29.4 mm long and 20.3 mm in diameter, as

compared to Y. baccata at 116.2 mm and 33.0 mm, respectively. Similarly,

the "tail" length is much shorter in Y. endlichiana at a mean of 2.2

mm than in _Y. baccata at a mean of 8.4. Seeds average larger in Y^,

baccata in both maximum diameter as well as in thickness (means,

9.58 mm and 2.19 ram) than in ]f. endlichiana (means, 7.3 mm and 1.9 mm,

respectively). Fruit length and width and seed diameter have high

loading values in Factor I (+0.931, +0.820, and +O.820, respectively)

and readily separate the two species on the basis of size (Fig. 6).

The amount of variation accounted for in the first three factors was

93.9%. Seed thickness loads heavily in Factor III at +0.808 but is

not sufficient to distinguish between the two taxa in that dimension.

Leaf data analysis (15 populations of Yucca baccata, 7 of

endlichiana) produces similar results for the pair; Y. baccata has

long (mean, 58.7 cm), wide (mean maximum, 31.7 mm, mean minimum, 19.6

mm) leaves with variable margins, tending to have straight, detaching

filamentous margins. Y. endlichiana has short (mean, 29.5 cm). 13 narrow (mean maximum, 9.7 mm; mean minimum, 8.0 mm) leaves with a much higher frequency of leaves possessing recurved free marginal fibers.

The first three factors account for 98.5% of the variability. High character loadings in Factor I are for both length and maximum and minimum width measurements (+0.867, +0.926, +0.966, respectively). The loading for presence or absence of curls on the margins in Factor II is +0.959. The two species are separable in the first dimension, as seen in Fig. 7, on the basis of length and width.

Flower data are not available for Y. baccata, but, from examination of dried collections and a review of the literature. Yucca baccata flowers are clearly much longer (5-14 cm or more; McKelvey,

1938) than those of Y^. endlichiana (mean, 21.2 mm, range 16-28 mm).

Furthermore, the maroon color of the latter readily distinguishes it

from any other species in the genus.

Flavonoid patterns for five individuals of Yucca baccata from

five localities and of one Y_. endlichiana are inconclusive. Although

Y. baccata had compounds present that were not detected in Y_.

endlichiana, the small sample size could very well account for the lack

of some of these compounds in the latter. In other species groups,

the greater the number of individuals, the more the less common

compounds occurred. In general, the overall flavonoid pattern for many

of the species in the genus Yucca is similar. Members of two closely

related genera in the family (Manfreda and Hesperaloe) showed quite

different patterns, retaining only a few of those seen in the yuccas.

Until extensive analysis of all compounds can be conducted, the

taxonomic value of general "fingerprint" maps for the genus is low. lA

Yucca camerosana and Y_, faxoniana

Yucca carnerosana and Y^, faxoniana are members of McKelvey's (1938)

series Faxonianae. They were described by Trelease (1902) as members of

the genus Samuela based on the presence of a floral tube with the stamen

inserted in the throat. Sargent (1905) moved both species to the genus

Yucca, and McKelvey (1938) concurred, indicating that the above-

mentioned character was not of sufficient magnitude to merit generic

separation. Indeed, some of the same trends toward formation of a

cup-shaped structure by fusion of the tepals at the base was observed by

McKelvey in plants of the Y_. baccata group.

Originally, Trelease (1902) designated the distribution of Y^.

carnerosana as extending from near Saltillo, Coahuila, southward into

San Luis Potosi, and the distribution of _Y. faxoniana as in western

Texas and "presumably extending into Mexico." Corey (1930) was the

first author to place Y^. carnerosana in the United States, based on

specimens from southern Brewster County, Texas, in what is now Big Bend

National Park. Since that time, additional populations in the Guadalupe

Mountains National Park also have been identified as Y. carnerosana

(Correll and iohnston, 1970). This extended the range to the entire

length of the Chihuahuan Desert, a long narrow strip down the center,

and at the same time limited the distribution of Y_. faxoniana to the

Sierra Blanca area in extreme western Texas and into adjacent Mexico.

It was the problem of distinguishing between the two species in western

Texas that initiated studies on this pair of species. Robbins et_ al.

(1980) examined 17 populations of plants from the stated ranges of both

taxa in western Texas and adjacent Mexico and concluded that, given 15 variability of the characters traditionally used to separate the two species and the considerable amount of overlap of these characters, recognition of two species in this area was not justifiable. This study encompasses additional populations from throughout the range of

][. carnerosana.

Data presented in table 9-12 represent a total of 40 individuals of Yucca carnerosana from 36 localities and 150 Y. faxoniana from 17 localities. The data were first analyzed using the latest recognized boundaries as given by Correll and Johnston (1970). Using factor analysis, separation was not possible on the basis of any character in

any dimension. Discriminant function analysis consistently incorrectly

classified a number of specimens as the opposing taxon. The alignments were then changed to reflect the ranges as Trelease (1902) designated

them: Y. carnerosana in southern Coahuila and San Luis Potosi, and

Y. faxoniana in western Texas and adjacent areas of Mexico. The data

were then reanalyzed. Although overlap still occurred, the pattern was

much clearer.

Analysis of the data taken from gross morphology of the plant

itself showed that, on the whole, Y. carnerosana tended to be larger

(mean height without inflorescence of 2878 cm in Y. faxoniana, and

4007 cm in Y_. carnerosana), but there was considerable overlap. The

number of leaf rosettes was greater in Y. faxoniana (mean, 1.21; range,

1-4) than in Y. carnerosana (mean, 1.06; range, 1-2). Yucca faxoniana

had generally larger inflorescences (mean, 1403 cm compared to mean,

936 cm for Y. carnerosana). The shape of the inflorescence in Y.

faxoniana tends toward more ovoid, whereas that in Y. carnerosana is 16

somewhat more globose. Finally, contrary to McKelvey's contention that

_Y. carnerosana panicles cleared the leaf tips of the rosette whereas Y.

faxoniana panicles did not, data collected in this study indicate that

both taxa show the same range in condition of clearance or non-clearance,

with Y. faxoniana clearing the leaves somewhat more frequently (65% of

the time) than did Y. carnerosana (48% of the time).

Factor analysis of these data accounted for 92.3% of the

variability in the first three factors. High loadings in Factor I were

shape of panicle (+0.813), height with inflorescence (+0.737), trunk

height (+0.796), number of heads and number of flowering heads (+0.781

each), and presence of curls on leaf margins (-0.792); in Factor II they

were height of panicle (-0.923) and height of inflorescence (-0.878);

in Factor III they were height without inflorescence (+0.547), number of

flowering heads (-0.594), number of heads (-0.549), and whether or not

they cleared the leaves (+0.508). When the factors were plotted against

each other. Factor I against II showed a general trend of Y. carnerosana

being larger than Y_. faxoniana. In Factor III against I, there was a

similar indication of size differences (Fig. 8). The Y. carnerosana

point lying well within the Y. faxoniana cluster represents a small

individual well within the geographic range of Y. carnerosana; this

might well have been responsible for its placement within the Y_.

faxoniana cluster. The Factor II versus III plot revealed no trends.

One of the key floral characters used by McKelvey (1938) to

distinguish between Y. carnerosana and Y. faxoniana was the length of

the floral tube (rarely more than 1.2 cm in Y. faxoniana and commonly

2 cm or more in Yucca carnerosana) . Robbins et^ al. (1980) demonstrated 17 that floral size was quite variable from population to population and could not be used to separate the two taxa. Although, using the older species distribution as assigned by Trelease (1902), one can make generalizations about floral characters between the two taxa, in no case is there non-overlap of measurements between the two. In general, Y. faxoniana has larger flowers but smaller floral tubes (mean, 75.3 mm and

12.6 mm, respectively) than does Y_. carnerosana (mean, 62.9 mm and 16.4 mm, respectively). Tepal width is greater in Y. faxoniana (mean outer,

19.2 mm; mean inner, 16.4 mm) than in _Y. carnerosana (mean, 14.7 mm and mean, 19.5 mm), and actual filament length is longer as well in _Y. faxoniana (mean upper, 23.5 mm; mean lower, 25.0 mm); equivalent measurements for ]f. carnerosana are mean, 20.2 mm and mean, 20.9 mm.

Overall smaller flower size in _Y. carnerosana is reflected also in the remainder of the measurements (Table 10).

Factor analysis of the flower data produced minimal separation of the two taxa in both dimensions II and I; 87.9% of the variation was accounted for in the first three dimensions. Heavy loadings in Factor I were for length measurements (total flower length, upper and lower filament lengths, pistil and ovary lengths, floral tube length, outer and inner tepal lengths, upper and lower filament attachments, and stigma length were all greater than +0.814). Loadings in Factor II were for outer and inner tepal widths (-0.696 and -0.615, respectively).

Figure 9 is a plot of Factor II against I, showing a general separation in dimension II on the basis of tepal width. Length measurements are not sufficient to clearly separate the two, although they do reflect the general trend toward larger flowers in Y. faxoniana. 18

Fruit sizes of Yucca carnerosana from 10 localities (17

individuals) and of Y. faxoniana from three localities (11 individuals) were extremely close (Table 11). Factor analysis revealed no means by which the two taxa could be readily separated by any suite of characters.

Leaf data for 40 individuals of Y. carnerosana from 36 localities

and 159 individuals of Y. faxoniana from 17 localities were analyzed,

but results were similar to those obtained for the fruit data set.

Although length of leaf averaged slightly longer for Y_. faxoniana

(mean, 67.8 cm; mean for Y^. carnerosana, 62.6 cm), the ranges were

roughly equivalent, with Y_. carnerosana showing a greater range (23-131

cm versus 43-114.5 cm in faxoniana). Similar situations were seen in

maximum and minimum width measurements. A greater percentage of Y_.

carnerosana possessed curling (rather than straight) detaching marginal

fibers than did Y. faxoniana. The overall average length and width

dimensions were reflected in Factor I in the factor analysis; 96.3% of

the variability was accounted for in the first three factors. There

were high positive loadings (greater than +0.9) in all three quantitative

measurements. Curls had a high negative loading (-0.952) in Factor II.

The plot of Factor III against I (Fig. 10) showed a tendency for Y.

faxoniana to have larger and wider leaves than Y_. carnerosana. There

was no such trend evident in any other combination of factors.

Flavonoid data were inconclusive. Data from 10 localities and 27

individuals for Y. faxoniana and 3 localities and 4 individuals for Y_-

carnerosana were obtained. Both taxa possessed compounds in common

that had similar high frequencies of occurrence; however, more compounds were recorded for Y. faxoniana. This likely reflects the high sample 19

size of Yucca faxoniana.

Yucca decipiens and _Y. filifera

^-"c^a decipiens and Y. filifera are the largest of the eight species

of indehiscent-fruited yuccas in the Chihuahuan Desert. This large,

arborescent pair of taxa occur in the southern part of the desert (Fig.

2) and appear to be western (Y. decipiens) and eastern (Y. filifera)

components of a closely related pair. Grouped earlier with such taxa

as Y. baccata and Y. torreyi (as Y. baccata), these plants were

regarded by Engelmann (1873) as arborescent forms of the more northerly

populations of the above-mentioned two STiEller species. Later, both

Y^. decipiens and Y. filifera were recognized as separate entities by

other authors. Chabaud (1876) named the eastern taxon Y_. filifera.

Engelmann (1873) had regarded it as a subspecies (australis) of Y.

baccata. Trelease (1902) then recognized it as a separate taxon,

Y. australis. Finally, Matuda and Pina L. (1980) placed it back into

^* f J-ll^g^a. Yucca decipiens, on the other hand, was regarded by

Trelease (1902) as Y^. valida Brandegee, but later (Trelease, 1907)

called it Y^. decipiens, separating it from the populations of _Y. valida

in Baja, California.

The two taxa are readily separable from each other in that _Y.

decipiens has an upright inflorescence that emerges directly from the

leaf rosette in a straight line and continues as such. Yucca filifera, however, has an inflorescence that takes a sharp turn upon emerging

from the rosette; the fusiform-shaped inflorescence hangs down. Leaves cf these two taxa are shorter and narrower than those of other

indehiscent-fruited taxa in the area. Both are easily distinguishable 20 from Y_. carnerosana in sympatric situations in having smaller trunks and smaller and narrower leaves. Yucca treculeana, which also occurs sympatrically in the northern portions of the ranges of these two species, can be distinguished by its longer leaves, smaller diameter

(and height) trunks, fewer rosettes per plant, and generally smaller size.

With regard to total plant dimensions, Y. filifera can attain greater size (one plant measured was in excess of 10 m) and has a looser-appearing habit. Yucca decipiens tends to be more compact with the leaf rosettes more closely grouped on shorter branches. The range of number of leaf rosettes per plant is highly variable for both species

(Table 9), but Y_. filifera averages slightly more at 7.18 heads per plant as compared with Y. decipiens at 4.4. The inflorescence of Y_. filifera is fusiform as compared with more ovoid in Y_. decipiens, and total length of the inflorescence is considerably longer (mean, 1064 cm versus mean, 840 cm). Some of this greater length is accounted for in the length of the stalk of the inflorescence before attachment of panicle branches (mean panicle length in Y. filifera, 752 cm; mean for

Y. decipiens, 631 cm). Further, nearly all (93%) of the panicles clear the leaves in Y. filifera, whereas only 4% clear in Y. decipiens.

Factor analysis of 52 individual Y_. decipiens from 24 localities and 68 Y. filifera from 25 localities showed 74.8% of the variation accounted for in the first three factors, with high loadings (greater than +0.9) in all the height measurements. Although it was not possible to separate the two taxa in any other dimension than Factor I,

Yucca filifera tends to be larger overall than does Y. decipiens (Fig.11) 21

Flower data for 21 Yucca decipiens (13 localities) and 56 Y. filifera (9 localities) show Y. filifera flowers not only averaged larger in every dimension measured except one, but the ranges, though overlapping in every case, were higher in Y. filifera as well (Table

10). The only exception was a smaller average stigma length in Y.

filifera (mean, 1.5 cm versus mean, 1.6 cm for Y. decipiens). This

size difference was reflected in the Factor II against I plot. High

loadings in Factor I were for total flower length and outer and inner

tepal length and width (+0.728 to +0.865). The two taxa were not

separable in any dimension, although the plot of Factor II against I

(Fig. 12) shows that Y. filifera tends to have slightly larger flowers

than does Y_. decipiens.

Fruit from 31 Yucca decipiens (17 localities) and 34 Y. filifera

(16 localities) showed considerable overlap of ranges; _Y. decipiens

averaged longer (mean, 67.0 mm versus mean, 47.7 mm in Y. filifera),

wider (means, 23.3 mm versus 19.6 mm), possessed a longer tail (means,

10.0 mm versus 8.9 mm), and has larger (mean, 7.3 mm versus 7.0 mm)

and thicker (means, 2.6 mm versus 2.0 mm) seeds (Table 11). All but

the latter measurement had high (+0.649 to +0.880) loadings in Factor I;

82.9% of the total variation was accounted for in the first three

factors. The two taxa (Fig. 13) showed only rough size tendencies in

the dimension represented by Factor I (size).

Leaves showed a similar trend to that seen in the fruit data. Leaf

measurements from 46 Y. decipiens (24 localities) and 52 Y. filifera

(25 localities) show Y. decipiens averaging larger in all directly

measurable dimensions but with considerable overlap with Y. filifera. 22

Leaf margins are variable, with Y. filifera tending to have recurved free marginal filaments more frequently than Y. decipiens.

In the factor analysis on the leaf data, 96.6% of the variation was accounted for in the first three dimensions. Loadings were high in

Factor 1 for the length and both width measurements (+0.861 to +0.931).

As can be seen in Fig. 14, a plot of Factor II against I shows a general tendency for Y. decipiens to have larger and wider leaves than Y. filifera.

Flavonoid data, as with the other taxa thus far discussed, are in­ conclusive. Eighteen individuals of Y. filifera (from 11 localities) and

31 Y. decipiens (from 17 localities) showed more compounds for Y. decipiens than for _Y. filifera, but as seen in other pairs, this might well reflect higher sample size for Y. decipiens. The few compounds that were recorded in _Y. filifera alone were in single individuals; no weight can be put on presence or absence of these compounds on the basis of such scanty occurrence.

Yucca torreyi and Y_' treculeana

Yucca torreyi and Y^. treculeana represent the most problematical species pair of the group under consideration. First described in 1858 by Carriere, Y. treculeana represents the eastern entity of this northern Chihuahuan Desert pair. The western component is Y. torreyi.

Characterized by a rather checkered taxonomic history, it nonetheless has been regarded as a western Texas-northern Chihuahua taxon. The bases for separation of these taxa are not always useful in the field, especially in areas where they occur sympatrically. An examination of

J ^sr^i--ir^r^c and kpvs niiblished by Trelease (1902), McKelvey (1938), 23

Webber (1953), Correll and Johnston (1970), and Matuda and Pina L. (1980) merely confuse the issue. All have acknowledged that Y. torreyi possesses free fibers detaching from the leaf margins. Matuda and

Pina L. attribute this character to Y. treculeana as well. The

remaining authors (except Trelease, who indicated that Y. treculeana

possesses denticulate margins) indicate that Y. treculeana has no free

fibers on the leaf margins at all. Most of the above-mentioned authors

also note that Y. torreyi has larger seeds than Y_. treculeana. The

most recent authors to deal with the genus (Correll and Johnston, 1970;

Matuda and Pina L., 1980) use a character involving shape of the carpel

suture (U-shaped in Y. treculeana, V-shaped in Y_. torreyi).

To the field worker, the most notable characteristic concerning the

two taxa is their similarities. To the east, the plants are taller with

bluish-green leaves, whereas to the west they tend to be shorter and

have more yellowish-green leaves, a circumstance that could easily

reflect edaphic and climatic factors. Where the two occur sympatrically,

however, one has a difficult time assigning the specific names given the

characters listed by any author. Thus, in the following initial

analyses, the plants were identified to one or the other species on the

basis of previously stated geographic distributions, and, in the case

of the confusing Cuatro Cienegas basin plants (in the area of reported

sympatry), they were assigned to species on the basis of plant size.

Factor analysis revealed no pattern of trends for the two taxa, and

discriminant function analysis consistently showed many mis-classified

individuals, all without any apparent pattern. The two taxa were then

viewed as a single variable taxon with more or less discrete components 24 based roughly on geographic regions. These groups were then analyzed using the new groupings (Fig. 1). These series of analyses were more helpful in that a pattern, albeit still not especially clear, began to emerge in the factor analysis. When a discriminant analysis was run on these new groupings, the plants were more often correctly placed into the pre-designated category.

Thus, the following discussion will deal with five rather than two groups: "torreyi," the west Texas-southern New Mexico populations;

"treculeana," the eastern Texas-northeastern Mexico populations (from

Uvalde, Texas eastward); "Del Rio," the populations in the arid Del Rio,

Texas-Sabinas, Northern Coahuila area; "Cuatro Cienegas," the group of populations in the Cuatro Cienegas basin in central Coahuila where the

two nominal taxa are said to be sympatric; and "Post," a disjunct

population of plants in the Post, Texas vicinity just off the Llano

Estacado escarpment near the southern high plains.

Gross morphological plant data were available for all groups except

for "Post" (Table 9). "Torreyi" was represented by 35 plants (12

localities "Del Rio" by 19 plants (8 localities), "Cuatro Cienegas" by

77 plants (23 localities), and "treculeana" by 66 individuals (32

localities). No trends were evident except noting that inflorescence

size was smallest (mean, 771 cm) in the western "torreyi" group and

largest (mean, 989 cm) in the "Del Rio" group. The "Cuatro Cienegas"

group was closer in size of inflorescence (mean, 813 cm) to the

"torreyi" group and the "treculeana" group was closest in size (mean,

894 cm) to the "Del Rio" group. Shape of inflorescence was similar in

all groups but the "torreyi" group; in the latter it tended to be

rectangular to elongate rectangular as compared to more ovoid in the 25 remaining groups.

Factor analysis of these data provided an interesting view of the groups. The first three factors accounted for 73% of the variation with a high loading of the three height measurements (height with inflorescence, height without inflorescence, and trunk height) and number of heads in the first factor (+0.993, 0.937, 0.947, 0.817, respectively). Figure 15 is the plot of Factor III against I and shows little other than the relative variability of the character sets in each group. There was no separation of groups in any dimension, but the plot shows both "torreyi" and "Cuatro Cienegas" to be quite variable, primarily with respect to size measurements. Both "Del Rio" and "treculeana," on the other hand, tend both to be smaller and have

less overall variability.

Flower data were taken on 13 "torreyi" individuals (1 locality),

13 "Del Rio" individuals (3 localities), 61 "Cuatro Cienegas"

individuals (15 localities), and 10 "Post" individuals (1 locality). An

interesting trend in size of flower was detected. The eastern groups

("treculeana" and'*Del Rio") had largest total flower length (means,

52.6 mm and 55.1 mm, respectively) than did the northern ("Post") and

western ("torreyi") groups (means, 44.5 mm and 41.2 mm, respectively).

The "Cuatro Cienegas" group, where both nominal taxa are supposedly

sympatric, has intermediate-sized flowers (mean, 46.8 ram). Most

length measurements showed a similar trend. Of particular interest

were the key characters commonly used by previous workers. Diameter of

the ovary was one such character; greater than 7.5 in torreyi, less

than 7.5 mm in treculeana (Matuda and Pina L., 1980), or greater than 26

7 ram in torreyi and less than 7 mm in treculeana (McKelvey, 1938;

Correll and Johnston, 1970). This character as specified by the latter two authors worked nicely; "torreyi" had a mean of 7.2 mm (range, 5-10 mm), whereas the other four groups averaged from 6.7 to 6.9 mm (ranges,

5-9 mm). Suture shape was also another character examined. Although

"treculeana" had a greater number of flowers possessing the U-shaped suture than did the other four groups, the character was by no means a consistent one for any single group. The "Post" group had the fewest number of U-shaped sutures. All five groups had suture states ranging from narrow V-shaped to U-shaped. This is a character that could well be environmentally influenced; for example, fullness of fruit might change the nature of the sutures.

A factor analysis showed 67.6% of the variability to be accounted for in the first three factors with the highest loadings in the first dimension by total flower length, outer tepal length, and inner tepal length. The second factor had a high negative loading for suture shape.

Figure 16 shows trends but no separations in the first two dimensions.

The "treculeana" and Del Rio" groups tend to have larger flowers, though variability is high in "treculeana." "Post" and "torreyi" populations tend to have smaller flowers; "Cuatro Cienegas" has somewhat intermediate to large flowers. In the second factor, the U-shaped suture in "treculeana" was of only minor importance.

Fruit data from "Post" was unavailable, but 100 "torreyi" from 19 localities, 8 individuals (7 localities) from "Del Rio," 23 individuals

(12 localities) from "Cuatro Cienegas," and 32 individuals (21 localities) of "treculeana" were measured and analyzed. "Torreyi" was 27 of note because of large size in all dimensions except seed thickness.

This group also was highly variable in all measurements. The

"treculeana" group, on the other hand, displayed less variability. The factor analysis (92.7% of the variability was accounted for in the first three factors) shows high loadings in Factor I in both width

(+0.925) and diameter (+0.900). The plot of Factor II against I in

Fig. 17 suggests that the eastern "treculeana" and "Del Rio" groups tend to be somewhat smaller and less variable in fruit dimensions than are the other groups.

Leaf data proved highly variable within each group. Sample sizes were 55 (21 localities) for "torreyi," 20 (18 localities) for "Del Rio,"

69 (23 localities) for "Cuatro Cienegas," 76 (42 localities) for

"treculeana," and 14 (2 localities) for "Post." No trend was evident

in any of the characters measured. In keeping with key characters

used by other authors, "treculeana" did have fewer individuals with

detaching marginal leaf filaments than did any other group, but this

character could not be used to distinguish between groups as previously

thought. Factor analysis plots produced no discernable patterns with

any combination of factors.

Flavonoids with this series of groups were inconclusive. The

sample sizes were: "torreyi," 87 (13 localities); "treculeana," 22 (1

locality); "Cuatro Cienegas," 19 (9 localities); "Del Rio," 6 (6

localities); and "Post," 4 (1 locality). There was no evident pattern

other than that which already has been noted for the rest of the genus:

the greater the number of sheets run, the more often infrequently-

occurring compounds appear. No consistent pattern was seen that might 28

serve to distinguish among any of these groups.

IV. DISCUSSION

Upon completion of the above data set by data set and species pair

by species pair analyses, a discriminant analysis was run on each data

set using all species (or in the case of the torreyi-treculeana complex,

the groups). For overall plant morphology, given the a priori

classification, the program was able to place the individuals to the

designated species with greater than 87% accuracy. Of 31 plants

originally identified as Y. carnerosana, only two were mis-classified

as Yucca decipiens. Of 71 plants called "Cuatro Cienegas," five

were mis-classified as Y. decipiens, and one as "Del Rio." Of 47 Y.

decipiens, two were mis-classified as Y. carnerosana, one as "Del Rio,"

and three as Y. faxoniana. Only two of 64 Y. filifera were

mis-classified as Y. decipiens. This suggests that gross plant morphology is rather reliable in identifying the species or groups.

The flower data set, however, was not so clearly defined. There was a 94% reliability in distinguishing Y. carnerosana from Y. faxoniana

and a 100% reliability of recognizing Yucca endlichiana on the basis of

flowers. Y. decipiens plants were correctly identified only 76% of the

time, "Del Rio" 69%, and "treculeana" 57%. The remaining correct species identification rate was 50% or less; "Post" at 50%, Y. filifera and "torreyi" both at 46%, and "Cuatro Cienegas" at 367., Fruits were classified correctly 100% of the time in Y_. baccata, Y. endlichiana, Y_. faxoniana, and "treculeana." Yucca decipiens was correctly classified

96 of the time, "Cuatro Cienegas" at 94^;, Y. filifera at 87/c. "Del Rio"

i^^'S?., ?^'^' ^^- fr=.s\rin>,gjrosana and "torreyi" both at 80'"^. 29

Classification by leaf measurements was difficult. Unlike the conservative nature of flowers in the entire genus, the converse problem is encountered here: leaves, even within a species or group, are extremely variable, likely reflecting environmental factors. Only

Yucca endlichiana and "Post" were correctly classified 100% of the time. "Del Rio" was correctly identified 94% of the time, "treculeana"

93% of the time, Y. filifera at 88% of the time, and Y. faxoniana at 66%.

The remainder had low values: "Cuatro Cienegas" at 42%, Y. carnerosana at 36%, Y. decipiens at 34%, Y. baccata at 27%, and "torreyi" at 25% of the time.

Clearly, some types of data are more useful than other in aiding in identification within this group of plants. For Yucca endlichiana, virtually all sets of morphological characters are distinctive enough to readily identify the species. Yucca baccata can be identified readily by using a combination of characters of gross plant morphology and fruit. Although no flowers were included in the analyses, examination of dried specimens leads me to believe that they are no more useful than are flowers for most of the other species. Leaves alone are not useful for identification of this species.

The Yucca carnerosana-Y. faxoniana pair are relatively distinctive, especially in their overall gross morphology. Flowers are reliable in distinguishing the two from other taxa but are of little value in distinguishing one from the other. Although the discriminant analysis was able to currectly identify Y. faxoniana fruit all of the time, it is not readily apparent from the individual measurements themselves.

Leaves are fairly characteristic for the pair but provide no aid in 30 separating the two.

Yucca decipiens and Y. filifera also represent a characteristic pair; they are large arborescent, many branched plants. Of most value in identification within this pair is total plant morphology. Flower and leaf characters alone are of relatively little value.

The greatest amount of difficulty in separating groups was in the

Yucca torreyi-treculeana complex. Although minor trends could be seen with respect to geographic groupings, no clear separation was seen.

Data obtained from throughout the range of these two taxa revealed a higher degree of variability than was seen in any of the other pairs.

From the preceeding discussion, it can be seen that identification of these plants is difficult, especially if only leaf and flower or fruit material are available. It can be seen also that there are few reliable characters for recognizing the different taxa within the group. One especially perplexing problem for the Yucca taxonomist is the impossibility of identifying the majority of species solely on the basis of, for instance, the flowers. Aside from immediately recognizing

the small maroon-colored flowers of Y_. endlichiana or the large flowers with the floral tube of Y. camerosana or Y. faxoniana, it is virtually

impossible to accurately identify the species of any other Yucca,

including an epiphytic species I have collected in southern Mexico. The

same applies to the leaves alone or to the fruit, or of the flavonoid

patterns. The degree of conservativeness of some of the characters

(such as flowers and flavonoid patterns) and of extreme variability of

others (such as the leaves) complicate the task at hand. The size of

the plant and the length of the life cycle further make difficult the 31

necessary task of cytogenetic studies. One must rely, then, upon a

combination of morphological characters that must, in light of the

presently demonstrated high degree of variability, be regarded in

conjunction with other such characters. The decision to retain some

species, realign others, and synonomyze still others will be made but

will remain tentative until biochemical and cytogenetic studies can

be conducted to clarify the nature and degree of genetic relationships

within the group.

V. TAXONOMIC CONCLUSIONS

Yucca endlichiana should be retained as Trelease (1902) described

it. It is clearly a separate entity and is readily identifiable on the

basis of floral, leaf, fruit, and whole plant morphological characters.

Yucca baccata, a long-established species also is retained. Its

non-arborescent nature, large fruits, and wide leaves allow it to be

readily recognized in the field.

Yucca decipiens is retained. A distinctive taxon, it likely is

closely related to the very similar Y_, filifera to the east but can

easily be recognized from the latter by the upright position of the

inflorescence, and the more robust overall appearance of the plant.

Yucca filifera is readily identifiable and should remain as it

stands. Although it is likely closely related to Y. decipiens to the west, there is no evidence of occurrence of hybrids in the area of

sympatry.

A realignment is recommended for the Yucca carnerosana-Y. faxoniana group. The variability is great enough to group the two into a single taxon, but I feel that until appropriate biochemical and 32 genetic evidence is gathered either to support or to discount this suggestion, the two taxa should be retained. Not only is the geographic distribution extensive, but there exists a hiatus in northern Mexico between the two taxa that could represent a barrier to gene flow. The geographic ranges are here redefined to concur with that given by

Trelease(1902), namely the range of Y. faxoniana be the west Texas- adjacent Mexico area and the range of Y. carnerosana as the southern

Coahuila/San Luis Potosi/eastern Zacatecas region (Fig. 3).

The most dramatic readjustment suggested is that of the Y. torreyi-

Y. treculeana complex. The high degree of variability across the range of these two taxa does not allow any set of characters to be used to define either taxon. Such previously-used characters as U-shaped sutures, slender ovary, and yellowish- or bluish-green leaves are not valid when large numbers of the plants from the entire range are examined. Hence, I recommend that all individuals in this group be placed under a single name, ]f. treculeana, with varietal recognition of the eastern Texas material referred to in this study as the "treculeana" group. LITERATURE CITED

Baker, J. G. 1892. A synopsis of Aloineae and Yuccoideae. J. Linn Soc, 18(108) :148-194, 18(109)195-241.

Chabaud, J. 1876. Florasion d'un Yucca filifera. Rev. Hort. Paris 48:432-434.

Corey, V. L. 1930. Contributions to the family Liliaceae. West Texas Hist, and Sci. Soc, Publ., Bull. 33, no. 3, pp. 32-36.

Correll, D. S., and M. C. Johnston. 1970. Manual of the vascular plants of Texas. Texas Research Found., Renner, xv+1-1881.

Engelmann, G. 1871. In S. Watson, Botany, King Report, p. 497.

1873. Notes on the genus Yucca. Trans. Acad. Sci. St. Louis, 3:34.

Hutchinson, J. 1934. The farllies of Flowering Plants. II. Mono­ cotyledons. London, xiii+1-243.

Johnston, M. C. 1979. The Guadalupe Mountains—A Chink in the mosaic of the Chihuahuan Desert? Pp. 45-49, _in Biological Investigations in the Guadalupe Mountains National Park, Texas (H. H. Genoways and R. J. Baker, eds.), Natl. Park Service, Proc and Trans. Ser., 4:xvii+l-442.

Mabry, T. J., K. R. Markham, and M. B. Thomas. 1970. The Systematic identification of flavonoids. Springer Verlag, New York, xii+1-354.

Matuda, E., and I. Pina L. 1980. Las Plantas Mexicanas del genero Yucca. Publ. in conj. with LANDI with the Governor of the State of Mexico, Mexico, 145 pp.

McKelvey, S. D. 1938. Yuccas of the Southwestern United States. Arnold Arboretum, Jamaica Plains, Massachusetts, 1:1-150+80 pis.

1947. Yuccas of the southwestern United States. Arnold Arboretum, Jamaica Plains, Massachusetts, 11:1-192+65 pis.

Pina L., I. 1980. Algunos aspectos sobre las plantas del genero Yucca. Pp. 13-20, iji Yucca, Serie el Desierto, Vol. 3, Centro de Investigacion en Quimica Aplicada, 330 pp.

Robbins, R. L., T. L. Burgess, and D. K. Northington. 1980. The Yucca carnerosana-faxoniana complex in west Texas and Mexico. Pp. 21-34, ^ Yucca, Serie el Desierto, Vol. 3, Centro de Investigacion en Quimica Aplicada, 330 pp.

33 3A

Rohlf, F. J., J. Kishpaugh, and D. Kirk. 1980. Numerican taxonomy system of multivariate statistical programs. State Univ. of New York, Stony Brook, New York.

Sargent, C. S. 1895. The tree Yuccas in the United States. Garden and Forest, pp. 301-302.

. 1905. Manual of the trees of North America (exclusive of Mexico), 2nd ed. 1922, Houghton Mifflen Co., xxvi+1-910.

Statistical Analysis System. 1982. SAS User's Guide: Basic. SAS Institute, 15 unn. pp.+923 pp.

Trelease, W. 1902. The Yucceae. Ann. Rept. Missouri Bot. Card., 13:26-133, 99 pi.

. 1907. Additions to the genus Yucca Ann Rept. Missouri Bot. Card., 18:225-230.

Wallen, D. R., and J. A. Ludwig. 1978. Energy dynamics of vegetative and reproductive growth in Spanich Bayonet (Yucca baccata Torr.). Southwest. Nat., 23:409-422.

Webber, J. M. 1953. Yuccas of the southwest. Agric. Monogr., U. S. Dept. Agric, 17:l-97+pls. 1-72, A-F.

Yucca. 1980. Yucca. Serie el Desierto, Vol. 3, Centro de Investiga­ cion en Quimica Aplicada, 330 pp. APPETiDIX 1: Key to the species. la. Plants non-arborescent; if possessing short caudex, then

decumbent; panicle completely enclosed within the leaves

of the rosette, or nearly so; flowers cream- or maroon-

colored . 2

b. Plants arborescent with 1 to several leaf rosettes on trunks

of varying height; panicle nearly completely within leaves to

clearing the leaf tips; flowers cream-colored 3

2a. Plants less than 54 cm tall, leaves triangular in cross

section, less than 15 mr. maximum width; flowers maroon, lying

nearly on the ground, fruit to 4 cm long Y^. endlichiana

b. Plants to 1.2 m tall; leaves blade-like, wide (to 45 mm);

flowers white, fruit to 19 cm long Y. baccata

3a. Perianth parts united at base to form floral tube into which

filaments are inserted; pistil averaging over 42 mm (range

17-80); flowers with sweet odor; trunk diameter beneath leaf

rosette usually greater than 20 cm; leaves 21-98 mm wide .... 4

b. Perianth parts not united at base; pistil less than 35 mm

long; flowers without odor; diameter of trunk below leaf

rosette normally less than 20 cm (average 15 cm); leaves

9-70 mm wide ^

4a. Plants commonly with 1-4 leaf rosettes; distribution in

west Texas and adjacent northern Mexico Y. faxoniana

b. Plants commonly with a single rosette, rarely 2; distribution

southern Coahuila to southern San Luis Potosi and

Zacatecas I- carnerosana

35 36

5a. Plants arborescent, often with up to 20 leaf rosettes;

leaf length 18.5 to 65.5 cm long), relatively narrow

(9-39 mm wide), flattened in cross section, with smooth

surface; distributed in southern Coahuila to San Luis

Potosi, Zacatecas, and Durango 6

b. Plants arborescent, with fewer than 8 rosettes; leaf

length from 36-127.5, width 16-70 mm; leaves U- to

V-shaped in cross section, with scabrous surface 7

6a. Inflorescence pendent, fusiform; relatively long individual

branches supporting rosette, giving plant an open

appearance ' _Y. filifera

b. Inflorescence upright, ovoid; short individual branches

supporting each rosette, giving compact appearance . . Y. decipiens

7a. Leaves somewhat flattened in cross section; functional

leaves upright, not dropping to lie flat against trunk

until fully senescent Y. treculeana var. canaliculata

b. Leaves U- to V-shaped in cross section; functional leaves

not all standing uniformly upright from trunk, often

hanging awry at various angles, giving plant a "ragged"

appearance X* treculeana APPENDIX 2: Taxonomic treatment.

1. Yucca carnerosana (Trel.) McKelvey, Yuccas Southwest. U.S., 1:24,

pis. 6-7, 1938; Webber, Yuccas Southwest., Agr. Monogr., 17:18,

1953; Matuda and Pifia L., Plant. Mex. gen. Yucca, p. 60, 1980.

Yucca australis Trelease, Ann. Rept. Mo. Bot. Card., 4:190, 1893,

as to Pringle specimens only. Not Y. australis (Engelm.) Trel.,

1902.

Samuela carnerosana Trelease, Ann. Rept. Mo. Bot. Card., 13:118,

figs. 1, 2, 12, 81, 85, 87, 98, 1902.

Plant arborescent, symmetrical, generally simple (occasionally

with two branches), to over 8 m (with inflorescence; height

without inflorescence to over 7.5 m; trunk to over 7.2 m. Trunk

dia. at base of rosette averaging 22 cm. Inflorescence

large, upright, ovoid, lower panicle branches clearing leaf tips

about half of the time. Height of inflorescence averaging 940 cm,

that of the panicle 650 cm. Leaves to 10 cm wide, to 130 cm long,

"apple green" in color, surface smooth with recurving detaching

filaments on margins. Total flower length 40-84 mm (mean, 62.9),

floral tube length 6-25 mm (mean, 16.4 mm), outer tepals 33-69 mm

long (mean, 46.5), 7-21 mm wide (mean, 17.4 mm), inner tepals

33-66 mm long (mean, 47.0 mm), 11-26 mm wide (mean, 19.5 mm).

Filaments of stamen insert in throat of floral tube 8-29 mm from

base in upper (mean, 19.5 ram) and at 6-28 mm in lower (mean, 17.9);

length of upper filament 13-28 mm (mean, 20.2), of lower 13-29 mm

(mean, 20.9). Average anther length 2.6 mm. Pistil 17-57 mm

long (mean, 44.2 mm); ovary dia. 5-11 mm (mean, 7.1 mm); carpel

37 38

sutures narrow. V-shaped. Fruit 31-99 mm long (mean, 65.8 mm),

20-33 mm wide (mean, 25.9 mm), with tail 5-36 mm long (mean,

16.6 mm). Seeds black, flattened, 6-10 mm maximum dia., 1-3

mm thick.

Type: Limestone Hills, Carneros Pass, Carneros, Southeastern

Coahuila, Mexico.

Range: On rocky hillsides, southern Coahuila, eastern

Zacatecas, western and central San Luis Potosi.

2. Yucca faxoniana (Trel.) Sargent, Man. Trees N. Amer., p. 121, fig.

106, 1905; ed. 2, p. 115, fig. Ill, 1922; McKelvey, Yuccas

Southwest. U.S., 1:18, 1938; Webber, Yuccas Southwest, Agr.

Monogr., 17:19, 1953; Matuda and Pina L., Plant. Mex. gen.

Yucca, p. 61, 1980.

Yucca australis Trel., Ann. Rept. Mo. Bot Card., 4:190 (as to

Texas plants) 1893; 13:117, 1902, as synonym of Samuela

faxoniana. Not _Y. australis (Engelm.) Trel. 1902.

Yucca australis Coulter, Contrkb. U.S. Natl. Herb., 2:436 (in

part), 1894.

Yucca baccata var. macrocarpa Sargent, Card, and Forest, 8:301,

1895. Not Torrey, 1859.

Yucca macrocarpa Sargent, Card, and Forest, 8:305, Fig. 42, 1895;

9:104, 1896, excluding synonomy; Silva N. Amer., 10:13, 1896;

Man. Trees N. Amer., 121, 1905, as synonym of _Y. faxoniana;

not Y. macrocarpa Engelm., 1881 or _Y. macrocarpa (Torr.)

Merriam.

Samuela faxoniana Trelease, Ann. Rept. Mo. Bot. Card., 13:117, 39

figs. 2, 11, 85, 98. 1902.

Plant arborescent, symmetrical, generally simple, often with two to four branches, heights to 6.9 m (including inflorescence), trunk height to 5.1 m, average trunk dia. 32 cm. Inflorescence large, 550-2550 mm long, usually broadly ovoid, often with the lower panicle branches clearing the tips of the leaves. Flowers

44-124 mm long (mean, 75.3 mm), floral tube variable, 1-32 mm long

(mean, 12.6 mm), length and width of outer tepals 39-108 mm (mean,

62.6 mm) and 10-30 mm (mean, 19.2 mm); inner tepal dimensions equivalent, with inner tepal slightly wider than outer. Upper filament attachment point in floral tube variable, averages 21.8 mm from base; lower filament attachment averages 19.6 mm; length of filaments 14-38 mm (upper) and 14-37 mm (lower), with means of

23.5 mm and 25.0 mm, respectively. Anther length 1-6 mm (mean,

3.9 mm). Pistil averaging 51.6 mm long (range, 28-80). Fruit medium sized, 36-136 mm long (mean, 67.1 mm) and 18-36 mm (mean,

23.0 mm) wide. Tail length variable, 9-36 mm (mean, 18.4 mm).

Seeds 7.7 ram in dia. and 2.9 mm thick. Leaf length 43-114.5 cm

(mean, 67.8 cm), 31-84 mm wide (mean, 51.2 mm); often with

conspicuous curling free filaments on margin. Leaves smooth,

"apple green," upright from the head, not lying against the trunk until they senesce.

Type: Sierra Blanca, Texas (!).

Range: Throughout the trans-Pecos area of west Texas, and extending into the northern parts of the states of Chihuahua and

Coahuila in northern Mexico. 40

3. Yucca baccata Torrey, Botany, Emory Rept. (U.S. and Mexico Bound.),

p. 221, 1859; Engelmann in S. Watson, Botany, King Rept., 496,

1871; Trans. Acad. Sci., St. Louis, 3:44, 1873; Rockroth Cat.,

Botany, Wheeler Rept., 270, 1878, in part, only as to plants of

acaulescent habit and northern range; Coulter, Contrib. U.S.

Natl. Herb., 2:436, 1891; Merriam, N. Amer. Fauna, 7:352, May

31, 1893; Coville, Contrib. U.S. Natl. Herb., 4:202, Nov. 29,

1893; Trelease, Ann. Rept. Mo. Bot. Card., 13:109, figs. 2, 4,

97, 1902; McKelvey, Yuccas Southwest. U.S., 1:30, 1938; Webber,

Yuccas Southwest, Agr. Monogr., 17:27, 1953; Matuda and Pina

L., Plant. Mex. gen. Yucca, .p. 65, 1980.

Yucca sp. Torrey, Botany, Whipple Rept., p. 147, 1856.

Plant non-arborescent, occasionally with short decumbent caudex;

occurs singly or in clumps. Overall height to 1193 ram,

inflorescence contained wholly within the leaves of the rosette.

Inflorescence to 82 cm long (average 63); ovoid. Leaves 30-99 cm

long, 20-45 mm wide. Fibers separating on leaf margins

occasionally recurved. Flowers commonly cream-colored, variable

in length (5-13 cm), pendent; slight formation of floral cup at

base of flower. Inner tepals slightly wider than outer; filaments

3.25-4.5 cm long, united at base into collar-like structure;

anthers 5-7 mm long; ovary commonly 4-5 times longer than broad

(occasionally 6-7 times); ovary dia. 7-12 mm. Fruit length from

50-182 mm and to 60 mm in dia.; seeds 10 mm in dia. and 3 mm

thick.

Type: Hurrah Creek, Guadalupe County, New Mexico. 41 Range: Eastern Mojave Desert, San Bernardino County,

California, east through southern tip of Nevada, southwestern

corner of Utah, northern three-quarters of Arizona, all of New

Mexico, south-central and southwestern Colorado, western Texas,

and extreme northern Chihuahua, Mexico.

4. Yucca endlichiana Trelease, Ann. Rept. Mo. Bot. Card., 18:229,

1907; Standley, Contrib. U.S. Natl. Herb., 23:1-93, 1920;

Matuda and Pina L., Plant Mex. gen. Yucca, p. 68, 1980.

Small, non-arborescent plant with diffuse rosette composed of

short (19.5-42 cm long) leaves that are triangular in cross

section. Leaves with recurved filaments separating from margin.

Inflorescence without main stalk; flowers on long pedicels,

spreading from base of inflorescence between leaves near ground.

Flowers maroon-colored on outside of tepals, cream-colored on

inside; pistil either cream- or maroon-colored. Flowers 16-28 mm

long; tepal width and length 15-27 and 6-11, respectively.

Filaments 3-10 mm long, anther length 1-4 mm, pistil 7-15 mm.

Inflorescence wholly contained within the leaf rosette. Fruit

23-40 mr:\ long and 17-24 mm wide; tail length 0-4 mm long; seeds

black, flattened, 7-8 mm in dia., 1-2 mm thick.

Type: Marte, Coahuila.

Range: Sierra de Parras, Sierra del Rosario, and Sierra La

Puila, Coahuila; area around Hippolito and La Rosa in southeastern

Coahuila.

5. Yucca treculeana var. treculeana Carriere, Rev. Hort., p. 580, 1858; 42

H^rincq, Hort. Franjais, pp. 163, 235, 1864; Engelmann. Trans.

Acad. Sci., St. Louis, 3:41, 55, 210, 212, 1873; Trelease. Ann.

Rept. Mo. Bot. Card., 3:162, 1892; 4:185, figs. 4, 5, 1893;

13:96, figs. 2, 18. 95, 1902; McKelvey, Yuccas Southwest. U.S.,

1:67, 1938; Webber, Yuccas Southwest, Agr. Monogr., 17:21,

1953; Matuda and Pina L., Plant. Mex. gen. Yucca, p. 75, 1980.

Yucca aspera Regel, Ind. Sem. Hort. Petrop., p. 24, 1858 (Jan.

1859); Gartenflora, 8:14, 1859; 8:35, 1859; Engelmann, Trans.

Acad. Sci., St. Louis, 3:37, 1873; pp. 210, 212, 1873, as a

synonym of Y. treculeana Carr.

Yucca canaliculata Hook., Bot. Mag., 86:5201, 1860; Engelmann,

Trans. Acad. Sci., St. Louis, 3:43, 1873; 3:212, 1873, as a

synonym of Y. treculeana Carr.; Baker, Jour. Linn. Soc. Bot.,

18:226, 1880, as a form of Y. treculeana Carr.

Yucca longifolia Buckl., Proc. Phila. Acad. Sci., 1862:8, 1863;

Gardners Month., 17:69, 1875; A. Gray, Proc. Phila. Acad. Sci.,

1862:167, 1863; Engelm., Trans. Acad. Sci., St. Louis, 3:42,

1873, as a synonym of Y. treculeana Carr.

Yucca argospatha Verlog, Rev. Hort., 1868, p. 393.

Yucca Treculeana var succulenta McKelvey, Yuccas Southwest. U.S.,

1:80, 1938.

Yucca Torreyi Shafer in Briton and Shafer, N. Amer. Trees, p. 157,

fig. 117, 1908; McKelvey, Yuccas Southwest. U.S., 1:104, 1938;

Webber, Yuccas Southwest. Agr. Monogr., 17:22, 1953; Matuda and

Pina L., Plant. Mex. gen. Yucca, p. 79. 1908.

Yucca baccata var. macrocarpa Torrey, Botany, Emory Rept., pp. 221, 43

1859.

Yucca macrocarpa (Torr.) Merriam, N. Amer. Fauna, 7:358, 1893, as

to name only; Coville, Contrib. U.S. Natl. Herb., 4:202, 1893,

as to plants of western Texas; Trelease, Ann. Rept. Mo. Bot.

Card.. 13:110, figs. 1, 2, 5. 86, 98, 1902. in large part. Not

Y;. macrocarpa Engelm., 1881.

Yucca torreyi f. parviflora McKelvey, Yuccas Southwest. U.S.,

1:112. 1938.

Yucca baccata Torr., sensu Engelm. in S. Watson. Botany, King

Rept., p. 496, 871, as to Mexican plants; Trans. Acad. Sci.,

St. Louis, 3:44, 1873 as to Wislizenus Mexican specimens.

"Y[ucca] crassifila Engelm. in Sched. 1848" Engelm., Trans. Acad.

Sci., St. Louis, 3:44, 1873, as a synonym of Y. baccata.

Y. baccata var. Q australis Engelm., Trans. Acad. Sci., St. Louis,

3:44, 1873, as to the Wislizenus Mexican specimens, not the

type of Y^. australis (Engelm.) Trel.

Yucca macrocarpa Trelease, Ann. Rept. Mo. Bot. Card., 13:110, 1902,

as to flowers.

Arborescent plants to 7 m high, usually with several branches, often in a clump. Plant often with functional leaves hanging at many angles, making the overall appearange often "ragged." Leaves yellowish- to bluish-green, with scabrous surface; usually U- or

V-shaped in cross section; 36-128 cm long and 16-70 mm wide. Leaf margins with detaching straight filaments. Diameter of trunk

14-15 cm; 1-8 rosettes per plant; inflorescence variable in shape, usually ovoid, occasionally clavate or spatulate, mostly included 44

within the leaves of the rosette. Inflorescence 180 cm long,

upright from the rosette. Flowers cream-colored, occasionally

tinged with purple; 27-81 mm long, with tepals 10-34 mm wide,

the inner ones slightly wider than the outer. Filament length

10-27 mm; anther length 1-6 mm, averaging 3 mm. Pistil 15-35 mm

long and 5-10 mm wide. Sutures between carpels U- to V-shaped.

Fruit 44-187 mm long and 18-46 mm in dia. Length of tail 3-41 mm

long. Seeds black, flattened, in the western populations 5-14 mm

wide (mean, 9.15 mm); in the other parts of the range 6.0-7.4 mm

wide; seeds 1-5 mm thick

Type: South Central Texas, exact locality unspecified.

Range: In the trans-Pecos area of west Texas, adjacent

Chihuahua and Coahuila, south through the Cuatro Cienegas basin,

scattered southward to Villa de Cos and Fresnillo area in central

Zacatecas; across southern Texas to the Gulf coast, and into

Northern Tamaulipas.

5a. Yucca treculeana var. canaliculata (Hook.) Trel., Ann. Rept. Mo. Bot

Card.. 13:97, fig. 2. 1902.

Yucca canaliculata Hook., Bot. Mag., 3:16, 1860; Baker, Card.

Chron, 1870; p. 1217, 1870; Engelm., Trans. Acad. Sci., St.

Louis, 3:43, 1873; Garden., 1:152; 5:134; Watson, Proc. Amer.

Acad., 14:252.

Yucca canaliculata pendula Koch, Belg. Hort., 1862:131, 1862.

Yucca recurvata Hort., in part.

Yucca revoluta Hort.

Yucca undulata Koch, Belg. Hort., 12:132, 1862. 45

Yucca treculeana undulata Hort.

Plant as described under the species, with the following

exceptions: number of rosettes commonly 1-2; inflorescence

nearly clearing the tips of the leaves; leaves dark green, less

U- or V-shaped in cross section (tending toward blade-shaped),

wider than in the other populations in the species with an

average of 43 mm (21-70 mm). Flowers 33-78 mm long, with tepals

averaging 17.4 mm (outer) and 21.0 mm (inner) wide. Fruit

averaging 81.3 mm long (60-109 mm) and 22.4 ram (18-28 mm) in dia.;

the tail is the shortest of the populations in the taxon at an

average of 7.9 mm (3-18 mm). Seeds are smallest in the group at

6.0 mm in dia. (range, 4-7 mm) and 2.1 mm thick (range, 1-4 mm).

Leaves uniformly upright, not hanging at random angles; overall

appearance of the plant is regular.

6. Yucca decipiens Trelease, Ann. Rept. Mo. Bot. Card., 18:228, 1907;

Standley, Contrib. U.S. Natl. Herb., 23:1-93, 1920.

Yucca valida Brandegee, sensu Trelease, Ann. Rept. Mo. Bot. Card.,

13:103-109, 1902; Matuda and Pina L., Plant. Mex. gen. Yucca,

p. 93, 1980.

Plants highly arborescent, to 8.7 m high; highly branched, to

30 rosettes per plant, often branching at ground level;

usually much branched higher in the plant; relatively short

branches supporting rosettes, giving plant a somewhat compact

appearance. Leaves 28-66 cm long, 13-39 mm vide, flattened, dark

green with slightly scabrous surface; often with detaching short 46

straight fibers on the margins. Senescent leaves hang down around

trunk, giving a shaggy appearance below the leaf rosettes.

Inflorescence upright, 49-137 cm long; panicle ovoid, upright,

rarely clearing the tips of the leaves of the rosette. Flowers

25-56 mm long; tepals 7-25 mm wide, inner ones slightly wider

than outer (10-25 ram versus 7-18 mm). Filament length 9-22 mm;

anther length 1-4 mm (mean, 1.9 ram). Pistil 15-31 mm long.

Flowers cream-colored, globose to campanulate. Fruit 46-91 mm

long, 16-29 ram in dia.; seeds black and flattened, 5-9 mm in dia.,

1-4 mm thick.

Type: Soledad Diez Gutierrez, San Luis Potosi, Mexico.

Range: The states of San Luis Potosi, Zacatecas, Durango,

Jalisco. Guanajuato, and Aguascalientes in Mexico.

7. Yucca filifera Chabaud, Rev. Hort., 48:432-434, 1876; Carriere, Rev.

Hort., 56:53; Garden., 10:554; Card, and Forest, 1:78; Baker,

Kew Bull., 1892:8. 1892; Card. Chron., 3:743. 751; Amer.

Florist. 8:59; Urbina. Cat. PI. Mex.. p. 353; Matuda and Pina

L.. Plant. Mex. gen. Yucca, p. 102, 1980.

Yucca baccata var. australis Engelmann, Trans. Acad. Sci., St.

Louis, 3:44, 46, 1893, in part; Watson, Proc. Amer. Acad.,

14:252; Baker, Jour. Linn. Soc. Bot., 18:229, 1892.

Yucca canaliculata filifera Fenzi, Bull. R. Soc. Tosc. di

Orticult., 14:278, 1889.

?Yucca perculosa Baker. Card. Chron., 1870:1088, 1870.

?Yucca baccata perculosa Baker, Jour. Linn. Soc. Bot.. 18:229,

1892. 47

?Yucca polyphylla Baker. Card. Chron., I.e.

?Yucca baccata circinata Baker. Card. Chron., I.e.

?Yucca baccata scabrifolia Baker, Jour. Linn. Soc. Bot., 18:230.

?Yucca scabrifolia Baker, Card. Chron., I.e.

?Yucca fragilifolia Baker, Card. Chron., I.e.

?Yucca baccata fragilifolia Baker. Jour. Linn. Soc Bot., 18:230,

1880.

?Yucca baccata Hystrix Baker, Jour. Linn. Soc. Bot., 18:230, 1880.

Yucca treculeana Rose, Contrib. U.S. Natl. Herb., 5, pi. 38.

Dasylirion aloefolium Carr., Rev. Hort., 1884:53. 1884.

Yucca australis (Engelm.) Trelease, Ann. Rept. Mo. Bot. Card.,

3:162, pis. 3, 4, 1892.

Plants highly arborescent, to over 10 m; to nearly 30 rosettes per plant; often with first major branch occurring at ground level,

Branches supporting individual rosettes moderately long, giving the plant an overall open look. Leaves relatively small, 18-56 cm long, 13-39 mm wide, often with fine, straight, short detaching fibers on the margins. Inflorescence hanging, fusiform, bottom branches of panicle nearly always clearing the tips of the leaves by a wide margin. Flowers cream-colored, 30-57 mm long, with a

"stringy" appearance (^.£. > not as succulent as other members of the genus). Tepals 10-24 mm (outer), 14-28 mm (inner) wide.

Filaments at 11-26 mm long; anthers averaging 2.4 mm (1-5 mm) long. Pistil 17-32 mm long, 5-10 mm in dia. Fruit 27-75 mm long,

12-25 ram in dia., with short (3-16; mean, 8.9 mm) tail. Seeds black, flattened, averaging 7.0 mm (5-9 mm) in dia. and 2.03 mm 48 thick (range, 1-4 mm).

Type: Coahuila.

Range: The states of Coahuila (southern part), Nuevo Leon,

Zacatecas, San Luis Potosi. Tamaulipas, Guanajuato, Queretaro,

Hidalgo, Michoacan, and Mexico. APPENDIX 3: Collecting localities by species, country, state, and county. Number of individuals from which material was collected is given in parentheses.

Yucca baccata. UNITED STATES. ARIZONA: Cochise Co.. 2.2 mi N

Jet. Hwys. 90 and US 80 (1); Gila Co., 8.6 mi WNW Ft. Apache on Hwy.

73 (3); 33 mi SW Carrizo on US Hwy. 60 (2). NEW MEXICO: Dona Ana

Co., £a^. 2 mi E Mesquite exit off 1-25 (58); Guadalupe Co. , Santa

Rosa, on 1-40 (1); Hidalgo Co., 10.5 mi NE Jet. Hwys. 70 and 80 (1);

San Miguel Co., 26.6 mi N Jet. US 84 and Hwy 66 (on US 84) (1).

Yucca carnerosana. MEXICO. COAHUILA; 28 mi E Parras (1); 1 mi

N Carneros (2): 0.7 mi S, 1 mi W Carneros (10). DURANGO. (1);

31.9 mi NE Guadalupe Victoria, on Hwy. 40 (1). NUEVO LEON. 6.5 mi N

Provideneia (1); 20 mi N Santa Ana (2). SAN LUIS POTOSI. 36.3 mi SE

Salinas on Hv^'. 49 (1); 38.4 mi SE Salinas on Hwy. 49 (1); 21.5 mi E

Boeas (2); 55 mi S. Huizache (1); 10 mi S, 9 mi W Cardenas (1); 15 mi W San Luis Potosi (1); 3.1 mi E, 1.0 mi N Huizache (2); 0.8 mi N,

3.2 mi W Jet. Hwys. 57 and 80 (1); 0.6 mi N, 3.2 mi W Jet. Hw>'s.

57 and 80 (8); 3.5 mi E Jet. Hwys. 57 and 80 (1); 15 mi S, 1 mi E

Huizache on Hw\'. 57 (1).

Yucca decipiens. MEXICO. COAHUILA. 34 mi SE San Pedro de las

Colonias on Hw>'. 40 (1); 12 mi NE General Cepeda (1); 43.6 mi SE

San Pedro de las Colonias on Hw>'. 40 (1); 51.4 mi SE San Pedro de las Colonias on Hw>'. 40 (2); 7.3 mi SE Hipolito (1). DURANGO. (1);

14 mi E Durango (1); 5 mi E Durango (18); 31 mi SW Gomez Palacio (1);

10.9 mi SW Jet. HWN-S. 49 and 40 (1); 7.2 mi WSW Guadalupe Victoria, on Hw>-. 40 (1). SAK LUIS POTOSI. 26.5 mi ESE Jet. Hv^'S. 54 and 49

A9 50

(on Hwy. 54) (1); 10.3 mi SE Salinas on Hwy. 49 (1). ZACATECAS. 5.7 mi E. Jet. Hwys 54 and 49 (3); 69.8 mi SW Concepcion del Oro turnoff

(on Hwy. 54) (3); 9 mi NW Fresnillo (1); 10 mi NW Fresnillo (1);

11 mi NW Fresnillo (2); 6 mi W Somberete (1); 14 mi W Somberete on

Hwy. 45 (5); 29.2 mi ESE Somberete on Hwy. 45 (1); 34.7 mi SE

Somberete on Hwy. 45 (1); 36.4 mi SE Somberete on Hwy. 45 (3); 39.9 mi SE Somberete on Hwy. 45 (1); 42.8 mi SE Somberete on Hwy 45 (1);

55.5 mi SE Somberete on Hwy. 45 (1); 18.6 mi W Villa de Cos turnoff, on Hwy. 54 (2); 30.8 mi W Villa de Cos turnoff, on Hwy. 54 (1);

38 mi E. Zacatecas (1); 17 mi E. Zacatecas (1).

Yucca endlichiana. MEXICO. COAHUILA. 4.2 mi E. Hipolito (4);

1.2 mi E Hipolito (1); 4.0 mi SW Hipolito (10); 4.1 mi SW Hipolito

(10); 4.3 mi SW Hipolito (1); 3.5 mi S Hipolito (1); 7.3 mi SE

Hipolito (1); 8.0 mi SE Hipolito (9); Hipolito (2); 2.0 mi N La

Rosa off Hwy. 40 (3).

Yucca faxoniana. UNITED STATES. TEXAS. Brewster Co. , 3.0 mi N,

2.1 mi W Stillwell Mtn. peak (1); 2.2 mi S, 2.6 mi E Stillwell Mtn. peak (1); 0.5 mi S, 2.7 mi W Stuarts Peak, 3300 ft (1); 0.3 mi S,

2.3 mi W Stuarts Peak, 3390 ft (1); 0.3 mi N, 1.9 mi W Stuarts Peak,

3380 ft (1); 0.3 mi N, 2.2 mi W Stuarts Peak, 3380 ft (1); 0.7 mi N,

2.0 mi W Stuarts Peak (1); 1.9 mi N, 5.5 mi W Sue Peaks, 3170 ft

(1); 3.0 mi N, 5.7 mi W Sue Peaks, 3170 ft (1); 11.5 mi N Sue Peaks

(10); 3.0 mi W, 10.4 mi N Sue Peaks, ca. 2900 ft (10); 7.3 mi N,

4.0 mi W Sue Peaks, £a. 3600 ft (10); 6.0 mi N, 0.6 mi W Sue Peaks, ea. 3800 ft (3). Culberson Co., Lower McKittriek Canyon, Guadalupe

Mountains National Park (3); Ridge S of Smith Springs, Guadalupe

Mountains National Park (9); Ridge N of Pine Springs Campground, 51 Guadalupe Mountains National Park (4); Above Bone Canyon, Guadalupe

Mountains National Park (4). Hudspeth Co., Sierra Blaca (1);

3.5 mi S Sierra Blanca (15); 3.5 mi SW Sierra Blanca (2); 7.7 mi

SW Sierra Blanca (1). Presidio Co., 6.0 km S, 18.5 km W Valentine, ca. 4700 ft (10); 1 km S, 3 km E Gettysburg Peak, ca. 4600 ft (10).

MEXICO. CHIHUAHUA. 10.7 mi SW Coyame on Hwy. 16, Sierra de la

Escondida, 1400 m (10); 20.4 mi SW Coyame on Hwy. 16, 1450 m (1);

21.8 mi WNW Benavides, 1550 m (10); 7.8 mi NW Benavides, W of Rancho

El Diamante, ca. 1400 m (10). COAHUILA. S end of Sierra del Carmen,

S of Mesa de last Fresnos, NW of Sierra de la Encantada (10); Nr.

Hacienda Santa Domingo, valley SW of Sierra del Carmen, W of Sierra del Caballero (10).

Yucca filifera. MEXICO. COAHUILA. 17.7 mi S Santa Cruz on

Hwy. 57 (2); 21.4 mi N Santa Cruz on Hwy. 57 (3); 14 mi E, I mi N

Parras (5); 15.7 mi E Parras (14); 19.2 mi E General Cepeda turnoff, on Hwy. 40 (1); 14.5 mi S Carneros on Hwy. 54 (2>; 2.5 mi N Hipolito turnoff at Arroyo Patos on Hwy. 57 (1). GUANAJUATO. 6.0 mi S

Jet Hwys. 110 and 57 (on Hwy. 57) (2). NUEVO LEON. 29.9 mi NE

Matehuala on Hwy. 57 (1); 30.7 mi N Matehuala on Hwy. 57 (3);

79.8 mi N Matehuala on Hwy. 57 (3); 47.5 mi NW San Roberto on Hwy.

57 (2). SAN LUIS POTOSI. 3.4 mi E Boeas (1); 4.5 mi E Bocas (1);

23.8 mi E Bocas (1); 8.1 mi NE Jet. Arista Road and Hwy. 57 (on

Hwy. 57) (2); 53.9 mi NNE Jet. Arista Road with Hwy. 57 (on Hwy.

57) (2); 14 mi E San Luis Potosi (1); 13 mi E San Luis Potosi (4);

2.0 mi N Huizache on Hwy. 57 (12); 3.1 mi E, 1.0 mi N Huizache (1);

55 mi S Huizache (1); 0.4 mi N, 3.2 mi E Jet. Hwys. 57 and 80 (2);

3.5 mi E Jet. Hwys. 57 and 80 (3); 4.9 mi E Jet. Hwys. 57 and 80 (3); 52 ZACATECAS. 16.1 mi SW Concepcion del Oro turnoff (on Hwy. 34) (2).

Yucca treculeana. UNITED STATES. NEW MEXICO. Chaves Co.,

Roswell (1). Dona Ana Co., £a. 2 mi E Mesquite exit off 1-25 (32).

Otero Co., Alamogordo (1). TEXAS. Brewster Co., 3.7 mi S, 3.6 mi

W Sue Peaks, 3000 ft (2). Calhoun Co., Magnolia Beach (2); 1.0 mi

S Magnolia Beach on Farm Rd. 2760 (4). Culberson Co., 80.5 mi E

Sierra Blanca (1). Dimmit Co., 9.0 mi S Asherton on Hwy 83 (4);

10.0 mi S Asherton on Hwy. 83 (2); 8.1 mi N Jet. Hwy. 83 and Farm

Rd. 1433 (on Hwy. 83) (1); 10.5 mi S Jet. Hwy. 83 and Farm Rd.

1433 (on Hwy. 83) (1); 5.4 mi S Jet. Hwys. 277 and 83 (on Hwy. 83)

(3). Duval Co., 41.9 mi E Jet. 1-35 and US 44 (on Hwy. 44) (1);

8.2 mi E Jet. Hwys. 44/59 and 16 (1); 20.4 mi E Jet. Hwys. 44/59 and 16 (3). Edwards Co., 37.7 mi S Sonora (2). Garza Co., 10 mi

S Post off. Farm Rd. 669 (15). Hudspeth Co. , Sierra Blanca (1);

2.4 mi N Sierra Blanca Country Club (1); 3.3 mi N Sierra Blanca

Country Club (1); 8.5 mi N Sierra Blanca Country Club (1); 8.8 mi

N Sierra Blanca Country Club (1); 3.5 mi S Sierra Blanca (5);

3.5 mi SW Sierra Blanca (3); 12.1 mi E Sierra Blanca (2); 13.9 mi

E Sierra Blanca (4). Jim Wells Co., 9.1 mi E Jet. Hwys. 44 and 281

(2). Kimble Co., 0.5 mi S Llano River Bridge on US Hwy. 83 (1).

Kinney Co., 27.5 mi SE Del Rio on Hwy. 277 (10). La Salle Co.,

14.1 mi E Jet. Hwys. 83 and 44 (1); 14.3 mi E Jet. Hwys. 83 and 44

(1); 2.0 mi E Jet. 1-35 and US 44 (on Hwy. 44) (1); 2.4 mi E Jet.

1-35 and US 44 (on Hwy. 44) (1). Reeves Co., Toyah (1). Sutton Co.,

0.6 mi N Sonora on Hwy. 277 (1); 3.9 mi S Sonora on Hw\-. 277 (1).

Uvalde Co., 25.2 mi S Leakey on Hwy. 83 (2); 25.3 mi S Leakey on 53 Hwy. 83 (1); 25.5 mi S Leakey on Hwy. 83 (3); 27.8 mi S Leakey on

Hwy. 83 (2); 31.9 mi S Leakey on Hwy. 83 (2); 32.0 mi S Leakey on

Hwy. 83 (1); 37.8 mi S Leakey on Hwy. 83 (3); 38.3 mi S Leakey on

Hwy. 83 (6). Val Verde Co., 54.3 mi S Sonora (1); 60.9 mi S Sonora

(1); 9.0 mi S Jet. Hwys. 277 and 377 (on Hwy. 277) (1); 16.6 mi N

Del Rio (2); 40.9 mi N Del Rio on Hwy 277/377 (1). Victoria Co.,

5.8 mi SE Victoria (1). Ward Co.. 24.1 mi SW Monahans on 1-20 (1).

Webb Co., 18.6 mi E Jet. Hwys. 83 and 44 (1); 31.2 mi E Jet. Hwys.

83 and 44 (3); 33.6 mi E Jet Hwys. 83 and 44 (2); 43.2 mi E Jet.

Hwys. 83 and 44 (4); 15.4 mi E Jet. 1-35 and US 44 (on Hwy 44) (1);

22.0 mi E Jet. 1-35 and US 44 (on Hwy. 44) (1); 27.2 mi E Jet. 1-35 and US 44 (on Hwy. 44) (1). Zavala Co., 3.4 mi N Jet. Hwys. 83 and

57 (1); 15.6 mi N Asherton on Hwy. 83 (4); 10.7 mi N Asherton on

Hwy 83 (1). MEXICO. COAHUILA. 26 mi E Parras (1); 6 mi SSW Cuatro

Cienegas (2); 6.6 mi SSW Cuatro Cienegas (11); 15.4 mi S Allende on

Hwy. 57 (1); 15.2 mi S bridge over Rio Sabinas on Hwy. 57 (1);

17.6 mi S bridge over Rio Sabinas on Hwy. 57 (1); 18.0 mi S bridge over Rio Sabinas on Hwy. 57 (1); 19.8 mi S bridge over Rio Sabinas on Hwy. 57 (10: 18.3 mi S Cuatro Cienegas on Hwy. 30 (1); 24.7 mi

SW Cuatro Cienegas on Hwy. 30 (1); 25.4 mi SW Cuatro Cienegas on

Hwy. 30 (4); 26.7 mi SW Cuatro Cienegas on Hwy. 30 (3); 24.2 mi E

Jet. Hwy. 40 with Parras Road (on Hwy. 40) (1); 25.7 mi E Jet. Hwy.

40 with Parras Road (on Hwy. 40); 23.3 mi S Nueva Rosita on Hwy. 57

(3); 12.3 mi S Castanos on Hwy. 57 (10; 2.6 mi N La Rosa off Hwy. 40

(1); 5.0 mi N San Miguel on Hwy. 57 (10); 2.0 mi N San Miguel on

Hwy. 57 (4); 13.3 mi N Santa Rita on Hwy. 57 (1); 2.5 mi N Hipolito turnoff at Arroyo Patos on Hwy. 57 (2); 26.7 mi S Monelova (at Zago 54 Microwave Station) (11). DURANGO. 30 mi SW Gomez Palacio (2).

ZACATECAS. 14 mi NW Fresnillo (1); 34 mi NW Fresnillo (2); 30.8

mi W Villa de Cos turnoff, on Hwy. 54 (1). APPENDIX 4: Specimens examined from other herbaria. All are from

the University of Texas (UT) except otherwise noted. A=Amold

Arboretum at Harvard University.

Yucca baccata. UNITED STATES. CALIFORNIA. San Bernardino ^.,

£a. 45 (air) mi E Baker, 5^$ (by air) mi S Ivanpau in New York Mtns,

5700 ft (1). COLORADO. La Palata Co., between Bayfield and Yellow-

jacket Pass (1). Montrose Co. , 7 mi NE of Nucla (1). NEVADA.

Clark Co., Kyle Canyon, 1400 m (1); Kyle Canyon, 1800 m (1) ; S of

Indian Springs (1). TEXAS. El Paso Co., Franklin Mtns., Tom Mayo

Mem. Park at N end, 5000 ft (1). Hudspeth Co., along Hwy. E of

Hueeo Mtns. Station E of El Paso 25 mi (2); 8 mi W Sierra Blanca, base of Quitman Mtns. (1). Jeff Davis Co., Madera Canyon, Davis

Mtns. (1). Pecos Co., (1).

Yucca carnerosana. MEXICO. COAHUILA. Sierra del Pino, Southern

Canyon (2); Near top of Sierra San Marcos, W of Reynolds Mine Head­ quarters on Casa Colorado turnoff W of San Lazaro Pass on Hwy. 56,

7200 ft (1). NEUVO LEON. Sierra Madre Oriental (1); Sierra Madre

Oriental, W side of divide below San Francisco CAnyon and Pablillo,

15 mi SW Pueblo Galeana, 8500 ft (1).

Yucca decipiens. MEXICO. SAN LUIS POTOSI. Ipina, Municipio de Ahualueo, 200 m (1).

Yucca endlichiana. MEXICO. COAHUILA. 6 km NW Las Coloradas toward Cuatro Cienegas via El Oso and Palomas, 1175 m (1).

Yucca faxoniana. UNITED STATES. TEXAS. Brewster Co., 10 mi E

Alpine, 4600 ft (1); Big Brushy Canyon (2); S of Persimmon Gap on

Road from Marathon to Boquillas (1, A). Culberson Co., South Fork

55 56 of McKittriek Canyon, Guadalupe Mountains National Park (1);

McKittriek Canyon (1). Hudspeth Co., 5-6 mi N Allamore, ca. 5000

ft (1); Indian Hot Springs, road not far from Sierra Blanca (2, A);

Road to Hot Springs, c_a. 3-4 mi below Sierra Blanca (3). Presidio

Co., along Box Canyon Channel above Junction with ZH Canyon (1).

MEXICO. COAHUILA. ea. 30 (air) mi WNW Cuatro Cienegas in limestone a. Canon los Pozos, about 3-4 mi W of Rancho Cerro de la Madera, along a- trail to Canon Desiderio (1).

Yucca filifera. MEXICO. COAHUILA. 6 mi W on Casa Colorado

turnoff of Hwy. 57 S of San Lazaro Pass (1). NUEVO LEON. Colonia

de Valle at foot of mtns., Monterrey (1); Vinero Propogaeion (1).

SAN LUIS POTOSI. 2 km E de San Lorenzo, km 62 Carretera SPL (1);

3 km NE Calera Municipio de Zaragoza (1); Venadito, Municipio de

Zaragoza (1); 20 mi E Saltillo, Coahuila [=Nuevo Leon?] (1).

Yucca treculeana. UNITED STATES. TEXAS. Brewster Co., 2 mi

E Alpine (1); N entrance to Big Bend National Park (1); Chisos

Mountains, Lower Green Gulch (1); Terlingua (1). Cameron Co., 10

mi W Boca Chica (1); 15 mi W Boca Chica (2); Near Port Isabel (1).

El Paso Co., (1); Franklin Mtns. (1). Garza Co.. 9.1 air miles S

of Post, ca. 2600 ft (1). Hudspeth Co., Road to Hot Spring, £a. 3-4

mi below Sierra Blanca (2). Jeff Davis Co., Limpia Canyon (1).

Kinney Co., Anacacho Mtns., 4 mi WSW of Cline (3). Live Oak Co.,

2 mi SW Three Rivers (1). McMullen Co., Hwy 59, 33 mi NE Freer (1);

21 mi W'of Three Rivers along Rt. 72 (1). Presidio Co., Hill behind

old Pool Ranch, Tierra Vieja Ranch (1). Terrell Co., 18 mi S

Sheffield, nr. Independence Creek (1). Val Verde Co. , directly S of

Comstoek on Rio Grande River (1); Del Rio-Comstock (1). Webb Co.. 57 Off US Hwy. 83, 5 mi S Laredo (1). Zapata Co., 5 mi S San Ignacio

Ramireno Ranch (1). MEXICO. COAHUILA. Sierra de la Fraqua, 18 mi S Cuatro Cienegas on Hwy. 30 (1); Sierra de las Cruces, eastern foothills, 7 mi N of Santa Elena Mines (1); ^. 15 mi below Pieaehe de Centinela (1). NUEVO LEON. Vinero Propogaeion (1). TAMAULIPAS.

Cuesta de Maurique, 500 m (1). 58

Table 1.—Classification of the Yucceae as per Trelease (1902).

Section Hesperoyucca Hesperoyucca whipplei Section Clistoyucca Clistoyucca arborescens Section Chaenoyucca Yucca filamentosa Y. flaccida Y. tenuistyla Y. constricta Y. radiosa Y. angustissima Y. Harrimaniae Y. glauca Y. Arkansana Y. Louisiansis Y. rigida Y. rupicola Section Heteroyucca Y. gigantea Y. gloriosa Y. reeurvifolia Y. flexilis Y. DeSmetiana Section Sarcoyucca Y. aloifolia Y. elephantipes Y. Treculeana Y. Schottii Y. brevifolia Y. australis Y. valida Y. baccata 59

Table 1 (cont.)

_Y. macrocarpa Y. Mohavensis Samuela faxoniana S. carnerosana 60

Table 2.—Classification of the yuccas of the southwestern United States as per McKelvey (1938, 1947).

Section 1. Sarcocarpa Series 1. Faxonianae 1. Yucca faxoniana 2. Y. carnerosana Series 2. Baceatae 3. Y. baccata Y. baccata var. vespertina 4. Y. confinis 5. Y. arizonica 6. Y. Thomberi Series 3. Treculeanae 7. Y. treculeana Y. treculeana var. succulenta 8. Y. Schottii 9. Y. schidigera 10. Y. torreyi Y. torreyi f. parviflora Section 2. Clistocarpa 11. Y. brevifolia Y. brevifolia var. Jaegeriana Section 3. Hesperoyucca 12. Y. Whipplei 13. Y. Newberryi 14. Y. peninsularis Section Chaenocarpa Series 1. Rupicolae 15. Y. pallida 16. Y. rupicola 17. Y. Thompsoniana 18. Y. rostrata Series 2. Elatae 19. Y. elata 61

Table 2 (cont.)

20. Y. utahensis 21. Y. verdiensis 22. Y. angustissima 23. Y. Standleyi 24. _Y. intermedia Y^, intermedia var. ramosa 25. Y^. kanabensis Series 3. Constrictae 26. Y_. constricta Series 4. Harrimaniae 27. _Y. Harrimaniae Series 5. Arkansanae 28. Y_. arkansana _Y. arkansana var. paniculata Series 6. Glaucae 29. Y_. glauca Y^. glauca var. Gurneyi 30. Y^. campestris 62

Table 3.—Classification of the yuccas of the southwestern United States as per Webber (1953).

Section Sarcocarpa 1. Yucic a carnerosana 2. Y. faxoniana 3. Y. schottii 4. _Y. treculeana 5. Y. torreyi 6. Y. schidigera 7. Y. arizonica 8. Y. baccata Section Clistocarpa 9. Y. brevifolia Section Hesperoyucca 10. Y. Whippleyi Section Chaenocarpa 11. Y. rostrata 12. Y. thompsoniana 13. Y. rupicola 14. Y. reverchoni 15. Y. neomexicana 16. Y. gilbertiana 17. Y. glauca 18. Y. baileyi 19. Y. angustissima 20. Y. constricta 21. Y. elata 63

Table 4.—Classification of the yuccas of Mexico as per Matuda and Pina L. (1980).

Section Sarcocarpa Series) Faxonianae Yucca carnerosana Y. faxoniana Series Baceatae Y. baccata Y. endlichiana Y. grandiflora Y. arizonica Series Treculeanae Y. treculeana Y. torreyi Y. schidigera Y. schottii Y. madrensis Y. jaliscensis Y. perculosa Y. decipiens Y. valida Y. potosina Y. filifera Y. elephantipes Y. aloifolia Y. lacandonica Section Clistocarpa Y. brevifolia Section Hesperoyucca Y. whipplei Y. peninsularis Section Chaenocarpa Series Rupicolae Y., rupicola 64

Table 4 (cont.)

Y. reverchonii Y. coahuilensis Y. rigida Y. rostrata Y. thompsoniana

•ieis Elatae Y^. elata 65

Table 5.—Measurements (in centimeters) and characters recorded on entire Yucca plants.

HWI Height of entire plant including the inflorescence or infructescence HWO Height of entire plant excluding the inflorescence or infructescence TKH Trunk height to base of functional leaves in the rosette TRK Trunk diameter at the base of the rosette of fuctional leaves HED Number of heads or rosettes on the plant FHD Number of rosettes supporting an inflorescence or infructescence INF Height of the inflorescence or infructescence from the origin in the rosette to the tip PAN Height of the panicle from the attachment of the lowest panicle branch to the tip of the inflorescence or infructescence SHP Shape of the inflorescence or infructescence (coded 1-12) CLE Whether or not the lowest panicle branch cleared the tips of the leaves in the rosette (coded 0-1) UPR Whether the inflorescence or infructescence was borne upright (emerging from the rosette and remaining straight or in line with the branch bearing the flowering or fruiting rosette), or hanging, taking a sharp turn once it has emerged from the rosette (coded 0-1) 66

Table 6.—Measurements (in millimeters) and determinations taken on each of 10 flowers per Yucca plant.

TFL Total flower length from the tip of the longest tepal to the base of the flower where it attaches to the pedicel FTL Floral tube length from the base of the flower to the point where the fused tepals become free from each other (only in Y_. carnerosana and Y_. faxoniana) OTL Outer tepal length measured either from the base of the flower (in the base of absence of a floral tube) or from the top of the floral tube ITL Inner tepal length, taken as in previous measurement OTM Maximum width of outer tepal ITM Maximum width of inner tepal UFA Position of upper filament attachment (only in species with a floral tube, where filaments of the stamen attach to the throat of the floral tube), measured from the base of the flower to the attachment point of the filament LFA Position of lower filament attachment, measured as in previous character UFL Length of upper filament (only in species with a floral tube, where filaments attach to the throat of the floral tube), measured from the point of attachment of the tube to the attachment of the anther LFL Length of lower filament, measured as in previous character AL Greatest length of anther PL Length of pistil from attachment point to tip of stigma lobes OL Ovary length, measured from point at which style starts to widen into the ovary, to the base of the ovary SL Length of the stigma (point of separation from style to the tip of the stigma) SLL Stigma lobe length, a secondary division of each stigma, often so deeply divided such that there appears to be six rather than three stigmal surfaces present 67

Table 6 (cont.)

OD Greatest diameter of the ovary SUT Shape of the carpel suture, when a cross section is taken of the ovary (coded 1-4) 68

Table 7.—Measurements (in millimeters) taken from each Yucca fruit.

LTH Total length of the fruit, including the "tail," which contains no seeds or evidence of seed development TAL Length of "tail" from tip to the point where the first seed is formed WID Maximum diameter of the fruit SD Greatest diameter of seed, taken on five seeds per fruit, from hilum to opposite edge of seed ST Greatest seed thickness, taken on same five seeds as SD taken, on side opposite the hilum SDM Calculated mean diameter of five seeds measured as SD STM Calculated mean thickness of five seeds measured as ST 69

Table 8.—Measurements (in millimeters) and characters taken from Yucca leaves.

LTH Greatest length of leaf, from tip to point where expansion of leaf base is at its maximum MXW Maximum width of the leaf MNW Minimum width of the leaf CRL Presence or absence or curling or straight detaching fibers from the margin of the leaf (coded 0-3) 70

i-i m ir\ n 1.^ 00 r^ CN ^^ f>i r> vC lr^ rsi -a en >0 -4 ^ J »- d PM C ON rg 1.^ f*^ CN* ^^ ^^ >-a» f-.M^ f^ I—« -» «

K> CC 00 PM P- ^^r^ '4 ff> ^ f^ 'n r> «• r» (N «J ir< 5 fs C .4 O ^ .J rn 1-1 r-i P» U r*. 1 lA I «^ I . J .-I d (.} r*. CN 00 m • PsI X -< 1-1 C -J o •* -^ — d m C 00 ^*

I fNI rvi .a 00 f^ c — -» m 1 ^ — O fsj X f^ — ^ X fvj O w^ rM c >C -- 00 f^ m in

.a — ^ f*N in L-> r-i O^ ^J -a ^ •£ O »n X" *? C I • j-i I • tNl I I _!-<-- — -H O \C c tc j ir* o fs r^ r-. -• o- 00 P^ .^ PSJ ^H .-I o

O 2 o X f^ 'Nj ^H r»i -J _. o — X c o O * *N .J ^ csi .a — 1/^ r>j »/-> — r>j «N >C

0. ON 0^ ON 0> O CM OC O NO pvj 5C r—N f*N X ^^ vO r>j r^ .^ r^ rsj O" —-

o O O o O O ON o- o c j f—1 ^ l/^ ^ 00 -c NC O oc i.'N m r-. I fNg 1 I a O •-' o^ c te ^ m ^ 1-1 c o -» fvj r-i OC -- c -J n 00 ~J OC

C ON ~J X

in — e^ m ^^ r^ 00 I • * ' • O C O o c c r~ .- (N r~ ^

.— u~ r^ O ON 1 ON o - - ccc -- — c r>i I." in. rsi ?—• •C

3 X 71

O.»N ON PNI PNl o -a — in 1-^ o- 1 m -J O ON 1 • • I O O O 00 C — ^yC CN in n pN( O O O

X sC -J m .-.r^. r^ m O .H NC ON n m -' -a X ^1^ in -*1 • 1 PM J'* kn ON• m — pj• o o c c o c r^ in o

in 9- _ r^ C O XI- — .^1 in• ^^ -- ^ (-N ^ P^ <•"' iC C O C ceo — X f^ (N

NC ^X^ -4 r^ p* cX r^ r>j in cr in -J —c p- 1 in —1 • t X X X X • p^ r-l ©CO o c c X ^Ni X -.J ^N m PJ P

C^ — "N r*. — Ln• in — — o o o ^vC- «c r^ u-^ *» rs* rv* r^j

NT r>j C -- O f-i c -» — C -1 — P^ ^ I • l~ I • . I • - I • O O O X ~9 X X r~ — -a PN* PJ ccc O- X — >.->

c Px m p.. — in O- .- 'Nl PM — C PNt -7 • I -» I • X I • ^ o c C -9 o o o e o c m O- c -? m p^ >3 PNI

NC c a in c NC P^ C o- — X P-. — X in -- C ON I • NC I • c o c c ri O «J p^l po — — ccc O -» in pNi P- o p.! PJ

in in p^ • I m r^ C -3 -» cC o c c o C C PM P-l

X P» -I —

C O 00 >£ c coo o c o o — •^ -- — c ^ in u ir> rsj cr

1—I a. UJ X 72

tr.

c X C "9 O X PM ON 00 PM -a o o p» it in m .c in • I . I . . I • e. o f-v O >c ^-, — .— r~ px PM .a — •* O O O f-N O >c -a P^ o rt AJ > • o 01 re r E ? AJ o c II •H O u 0) U C:- u E -H o O rH X X e 0) a ^.f ^^ in «0 p^ O .a PM X O ,C r» >-, . I • C- - c •Wi -H • I cr. K OOC r^| re E II O 3 V- •• M r re K o PM P^ -J rsi r^ ^ -C PM -- u: o • c X ~ -r . t . . I • . t • I p. — — c Ki re i^ p^ X COO iC .£ X >C P« X >0 C P^ c -r c r- o c o ^ PsI ^- — c ^ C C E -^ E ^ a; c cJ u C; s-^ -1- .H c )- w P u k-

::; re p^ p; p^ = K — 1- X X ~- -r K cr -0;r ^ X X l£ ^M PW X •; PJ cr 0/ .; i" C ^ -^ ON re -o O II m X C CCC m 1- re K m p- — ir ,-N _ c -J (D 0) "^ *.= E K E T5 J-i II H C —( O O u: : O E < u- r-: re I— ir. iP c- •? f- PS C >p . I • u re| tr; in .— PM p- a c re o c c C X ^" c ^ »P o • oo s O PM C AJ re &:• •r- 3 X o c re c c c V. re o o c: X .- o ^ o o o re .J PM in ON -M -J CI, e- i~ » PM iP ^ o re c c u u. sC p^- o ^ ' 11 re re o -c < 3 •o re 0) u- o CI. r re -, II re jr re iC IP c^ C m »» p. - .- p. -, X AJ O cr u. — C «n c- . I . . I • I c . I pg P* PM iP C PN- c c re c • J I.- ^ CCC C i' C NP NC re cy ir .a p >-l to o 0) II c >^ •c < re o o re ^ re c „ NC 0 C .i -a PS -^. C k^ '" o- X p» PM tP 0) 0) >-i - • I . 1 . • 1 s- r^ r^ C — • XJ X re PS C C" NC NC -a 5 p^ cr — ^- u c X sT c ^ 0," "H ,»—s re re >- m -^. c :? p" - o 2: I c, cr I AJ > -^ u\ c O- — C ON "-s X l** Ps X r-l c • I I c u, o . I 0) ID r • PS' Pv r^ C in PM p^ X — _ ^ p. CCC C k^ p^ . a AJ W E -^ b. sC PM .— o o tr —, c; PM — r-( cr — iJ P-. a 0) • II --I 0) E >;- ,r 3 a; u O CL re c ?< H O c c r a re &/ t- 73

-a X P» PM ^ .a m -• o f^ -a PM 00 .» -a NC • 1 • I • • I • • 1 • I -a PNI 1-4 ^ o I I I I I I© PM PM p< p* •.< X GO '-I ^M PM PM -<

O PM sC o NC X r^ P^ P^ O PM -3 • I • I p^ _ o .a X p-i o .a PM PM ^H ^M PM p-

CP X >r ON PI ^.1 o

in P"* i^ ON r~ p^ X ^H pj p^ O .- r^ * I • t p,% ps PM O »A PM 1 ^ O r^ -4 PM PM — O PM — PM PM

(^ ^j ^- s:r ^ >c

tf r^ C PNl X c 1"' r^ ^^ C .— PM -J

X -? in c X PM O • I r^ PS ^ r~t PM -- — — — O

r-t f-> s» PM -O \r\ O • I • in r-' OC pvi P^ —4 — C • O J, in ON PM r^ ^- "^

O -9 c O sC cc:^ ^ox'Nl ci^o- X

ON p- in sa p^ p^ c ON ® ^ in ,^4 PM i-*^ ON ON PM ON . I m PM X ON PM Ps- . I . • ' • • I O — NC . I . . I • C P^ PM r^ ^ _ -a r^ Nt o- a s p» NC -a C P" PM si PJ M 1-1 pg ^-

c O V in c sC — -a '- X ^ l.'N • 1 O^ w^ r4 I • -I I I I ^ r-1l -. PM — C PM

0)

.J .J CO < H 74

X •a — I I -M .- O ^ in o p.. PM -M

ON ON

C — — PM ^^ -^

c r^ .— C^ P^ _ _ I

O ON — X m -J pj • I PM .- —

ceo lO iPi C

PM r^ in • I — ,- o

sj ^ c- O

C O o

O^ ^^ p-l PM X sC . I . • I • o O C o NC «n c — — o

0)

re -J c pj c m 75

(A >i~S c • ON o en £ CNJ X X •H U K • P^ pcM PS ON p^ X .^ PM 0> PM X X PM sa »n • 1 • t . 1 • 1 • • 1 • ps r^ p^ AJ C -M PM PH O iH 0) o 3 e •,: en a -H >" II 0) O «-l II = •H O. rH < Cti I^M^ NA O "H U O PM ^^ '{J • PM t—« X ON PM Ps -a p^ ON -a o- -c lO in Ps. 0) * E = • 1 • • 1 • • 1 • CL en "N PM PM -1 O sj P. p- p^ .a -a X •". r~ >© O en -—i c re r ^-' X -a -^ p-i PM P- re •H 4J •> u 3 re -H O "O i M_i -H M U OJ > re tOi M p-t en -H Xi\ u PM X ^^ AJ tJ en o t r^ m — .n. O -^ m P-. r-N r-- 1*1 X M-l p- -a NO OC * • 1 • t • ps p. P^ P^ PM O C C AJ • AJ O CO PM X P^ P- iC O Qj -p^ C J^ r oa- cX --^1 pM PM r4 E ^^ * r i r- in o PM — O P-. pH U-l AJ C •,>-'l = ^-^ .a PM '^ J.I -H >! II re OJ i .—• O ^' P-I p^ ^ -.1 p^ in o PM P- O .H re o en 3 -H AJ •H u ^" 0) X AJ 3 CI. AJ •o re re flJ "^ • 3 o E o II 1 •O X "^ 03 0) z tj .H UJ P "O pi N£> re X •^ 3 H /"^ NC 13 c AJ en • i ON -a in < • .* r-l p"N O i~ X Ps ON yC 3 3 to >-l • t • • 1 • 1 • • 1 re 0) 0) re M 3 31 w y-*N C ON C en o o CO O -1 -H -- PI in re X ON -c ON P- ON • t • • 1 • .1 (fl 0) -H •PH < • 1 • • 1 • 60 U r^ X NCI PM PM p- O 0) »n p-l ^ .£1 in o in c ^ cn ej D. AJ 3 pM PM PM PM c) o en a. o 3 60 3 -^ X ^X J-i CO Ti PM re o o i^-i u c in X -a PM P^ sj j-i -o re en PM — P- O sC — u 3 H -^ to C/ 76

eo AJ ON en I o in PNj p^ 0) AJ •« en -a in p-» r^i in PM m sj o o • I • I • I o PM X -a p~ ON ps .C — O O »-i 3 to ft. -a w re o; 3 r^ ^7 •—I PI PM o E to en re -H en AJ r-4 X 0) C "H o O m Pi H r^ X PM O ec - p- -M -a . I 0) en 0) 3 TJ I 3. TJ .£ fPN P- ON c e -M >-t -H 3 p» ,a —• -» PM en re 3 60 (U 3 re V4 "o reen VreJ G) E >-l IAM > E in O NO •H : pj PM u • sS — o i- .£ p-l pn sJ r^ T't C K TS re II • I • • I O -^ NO — O — AJ 3 r NC O- X ON C fH < .-^ ^ p-l p- E It- "TS • cj en o cj en Ul 0) 60 X 3 3 N c 0} C3 (D pj -J CP X • • I en O, I—I "H D C r-l p^ in — o c re en "o >s>A- c X PM P- sj «H 3 a en G) -H AJ 0) U c O^ r^ fSZ 3 4J re "3 o p- J.-, r^ ON -^ >C • I en c o c O •H p- X NC P^ a *n 0) c ^ £ S.^ P- ^4 0) en re 3 o re 3 •H U AJ O •H re 3 X AJ > 3 en 0) re re 0) X < sT PM a X II II rex en cj /^ < = CM tXM o •o u m c .3 re sJ pM re a) o AJ re rsi OC -^ C N'-' -^^ ON PNJ ON X 3 < • X — o • I AeJn ,3 re/^ X ^\ en o » "3 tO • I • > AJ Pi re 'll (0 en o AJ >-|g Ul -033 ^ 4J c II O o- ON in I C P' NC 0) 0) en ej p^ m in ps ..r o~ ^ ^M X en • I • I • < ' ON PM P^ 3 ut o 03 r X C X p- C 1/^ — c c 3 CO X p-l ps re U re X ^1 •, - in rN ^- 0) tAM Qj o- re —' i /-s AJ >, • I AJ en en /-^ to 43 w c Ul -^ o >-i 3 I C r- PM P- PM -I I 3 m sPi ^ m o 0) o »-i o • 03 X sC — —CO .H AJ • eu O -H 5 ^ ^ \r\ CM U PM PH 4J 0) 0) X AJ AJ e.n. re E 3 = « Q) X "H "H O *, II "Ti pa.j ^ 03 3 -^ 3 SH|r 3 o X -3 arH JL £ ^ X to 3 0-Hp

85 3 n

IH< •^

O (B rt 3 O. O i—» -ti H« O "Tl 3* (D M. r> (U ft 3 o &} fi

n o en 0) o oo Q. 0> p. n 3 H" Ul l-J rr n H-* 'Ti i - fD 03 C/1 o s.-/ rr o -3 •1 O "3 M 3 l-» i-h Ck> o rr fl H- o t. 3 3* en o • l-» 0) "3 I—* CD 3 rr O. CD rr Q)

o >-« 1^

O o Qi rr 0) O "3 s r> fl O l-» (D en 0) 3 3. 86

in in f in

< CD \ \ \

in

O 87 "3 3 CO

en 03

O u

3 03 a o

re AJ re o u re X

3 O re AJ re •3

AJ •H 3 Ul • l4-l e3n Ul O •H u-ol 4J M freH 3 Ul D. 0 O AJ o. u /-N tire- 0cn) AJ 1—1 en o 3 Ul •H •pi CJ 6re0 'V re 0) t—1 M 0cn y-i U •*-u• AoJ o re re 5 u. •reH U-l X O O •H AJ iH 0 T3 1—1 3 PL, 0)

0) Ul 3 60

88

A o 1 \ \ Vl \ \ \ \ \ \ \ TV** \ •1 \ / \ / \ / \ / \ < / \ * / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ p / \ o / \ f \ 0 / \ o / \ / \ / •

/ N \ \ / \ 1 s 1 \ / CM / V • OO

in O) 00 CO 6 "3

en 0) iH U Ul •H O 3 03 a o re AJ rt a u re X

AJ re -3 tM re 0) • iH « 3 Ul O iH u-ol JJ re M r-^ 3 Ul D. o O AJ a CJ re /-v ptM cn 0) AJ .—1 en u 3 Ul .H •H re o 60 re •3 03 M cn M o 1-1 Ul o o N.^ AJ o re rt 3 (XM rt •H U-l X o a •H AJ ^M o •3 iH 3 CLI 03

03 Ul 3 60 90

r* /'" \ 15 b " \ \ \ \ « 1 \ « 1 1 \ 1 1 \ 1 \ < 1 \ 1 \ 1 \ 1 \ / \ / \ o/ \ \ / \ / "^ ^ / N. 0 O 0 >* >» • ^

^••«- c ^^<^ /^ ^ - / N / \ / \ / \ / \ / \ \ \ \ \ 1 z \ 1 ^^ \ \ \ \ \ 1 \ 1 \ / \ / \ • • • / / P5 \ \ • ^^ ^

O CoM 9> CM 91 n g CO o u 03 3 U re u

en 3 O

AJ rt 3 a 0 a u o u-l vi AJ re •3 4J 3 re . fH /—N a cn 03 03 iH »H O o Ul X •H 5 tJ Ul TJ o 03 u-l cn o M .H O Ul N^' o AJ re o 3 re re UM •H 3 AJ O tn X 3 re •H ^LM re 60 • re >-l M '3 M 3 M re u /T^ o cr AJ 03 o Ul rt re ft, 3 cr u-l cn O 3 AJ 03 0 a »H 0

00 03 Ul 3 60 92

r- 93 s 3. O

rt

en O Ul 03 E rt u

en 3 O

re fH 3 oa CL 3 O rt AJ re T3 Ul 3 ? o cn 03 Ul o o u

•3 U4 0) o cn AJ O U .H re o PXP W AJ re cn c c re re c 6C o re X re

Ul >\ o CJ 3 rt re

cn 03 Ul AJ O re 3 cr cn

0) Ul 3 60 94

\ 00

/ • • / / / / •

\ -V- \

<

\ < \ V

CM o

CO CO CM 00 6 95 o

(0 3 rt otn Ul 03 £ rt C3

en 3 O •H AJ re f-t 3 Ou 0 c 3 o re AJ re •3

U..I re . 03 /-^ .H cn 03 Ul r—i O o U-l Ul •H M o Ul •3 0 03 4J cn u o rt iH ft. o ^p^ AJ cn re 3 c •H re re .p-l 60 c re 0 X (H re M L— M

Ul >> O AJ •3 V 3 re re ffc ^-v u-l cn O 03 U AJ re o 3 fH cr pH cn

0) Ul 3 60 96

\ \ \ \ •I I \

• •

/ \ •N

>'' r-- '" /

I <

in CO CO

^^ ^^ ^H CM 00 in oo IT. 97 rt Ul 03

to 3 o •H AJ rt r^ 3 CL c a E o Ul u-l rt AJ rt •3

XJ . 3 /-N re en fH 3 a Ul fH 3re re cr u cn O 4J 3 03 U-l CM O o N-^ M en Ul 3 o 3 4J .rH o 3. ti T-^ o u. 03 AJ TS cn 3 • >- re 60 TJ re 3 rt IH H^ /—V cn Ul 03 o iH AJ o V Ul re n-l fi- u U-i '3 o 0) en AJ o o iH iH o Pui S-.'

03 U 3 60 98

oo CO y in y N y \ / \ / / • \ / \ / \ / \ / / \ / \ / • \ / \

/ • 1 / 1 / 1 / / 1 1 • • • • t !

.• • \ \ y^' 1. ^ 1 \ 1 I A' Cf a 1 / 1 \ / \ / o / /

/ ^ — S / y y y \ = y m o

1 Vi.,= O r^ o CO 99 •3 03 0) O

rt Ul 03

tn 3 O •H AJ

ireH 3 3- O CL

3 O re 4-1 re •3

Ul 03 ^ O r^ . U-l ^v

Ul 3cn Ul u-ol re3 M cr cn Ul 3 AoJ 0) 3- o O [reb N-^

AJ en 3 c3n •H .—a>^ re .CM 60 o re 0! |H •3 M • U >- 4oJ •3 CJ 3 fret re /—s u-l cn O 03 t—! AJ u o Ul p^ a

CM

03 Ul 3 60 100

in CO

^^'*""***^ y >*^ / . "^v / ^w /

^ • / NX • ! \ ^v '• « / \ / \ Ss • . / ^ 0 / \ / ^x • ° / \ / ^^--' \ / \ 1 ^\ 1 1 1 \ / / / \° uu • / \° / \ / \ y \ y y \ y \' " 0 y N y y CM ^» ,^ .^ *"

I in lO in m 00 101 •3 03 0) o

rt u 0)

tn 3 O •H AJ ireH 3 CL 3o. E oUl u-l re J-) re •3 AJ •H 3 • VM /«-v u-l tn 3 3 u O re 3 M tr Ul en O 3 AJ 03 a 3. O fret >»• xj en en 3 3 03 .H •H re 3. 60 •H re u3 M T3 1—1 • M >- O AJ •3 CJ 3 fret re ^-N u-l cn 03 o fH AJ O o Ul c^ o

cn

03 Ul 3 60 102

^^^ """•"v y V y y \ y \ y \ y \ \ ? / \ / 1 / ° a 11 UJ 1 / Q 0 ' / \ 1 1 •^^^^. V 1 1 1 1 1 1 1 **, o 1 1 1 • 1 \ 9 "^ / N / •w, • a \ / I • \ \ \ \ • \ / A N s • / \ X y •x X a ^^ \ "-X ^*,^ • 1 • • 1

/ •/ \ o \ p«' «

CO CO r«- 103 •3 03 (A O

re u 03

cn 3 O •H AJ re 3 CL o a 3 O re AJ re •3 u-l rt 03 rH /—.s cn Ul 03 o Ul U-. re3 M cr en Ul

AoJ 033 o CL O fret V—' AJ en 3 c3n 03 •H •H re 3- 60 •PM rt o03 M •3 (H • Ul >- AoJ •3 o 3 fret re

u-l /~\ 0cn3 o r—( AJ O o ^ ^ u

0) Ul 3 60 104

CO o CM

a °v \

-0 \ f \ %

» i

a //

y^ /

y y.

o 00 (O

CO o CO 105 3 0 03 •H O. (t 0 "w r-l 03 : O •^ ^ ^>^N ^ 0) •3 3 fc rt o AJ «« = ^N tn u-l 03 0 •-• 60 en c 3 re O -H •H U. AJ J_) re rH 73 3 03 CL ^ o o O. r-\ CJ Ul ^-' 0 u-l z en rt rt AJ 60 rt 3 •3 3 03 AJ -H 3 U re ^ o CL Ul 4J fH re rt 3 AJ CJ o = AJ A Ul /-s o cn LM C3 fH M CJ Ul Ul -H o o 4J C "3 rt 3 ft cn 0 AJ iH cn u 3 ^ •H • re : cn 60 ct! 4-1 re c c re re M CD t—1 M ^ a M 3 O /P-s U 03 cn o u •3 AJ AJ 3 o = 0 re E ft •> re /—s •H u-l cn •3 O 3 rH 3 AJ O 3 o »- 3- iH •^ O pu, U

in

03 Ul 3 60 106

CM CO

CO

/ /o / / / \ / / u / ^

I I i I \ I

\

I ° -« 4 y^ o ® "*^"V^

f \ * o < \ ^, •••, 0\ • 4« \ s / in o oo o I O) CO o CO o 1 107 0) 0 AM 0 r Ul AJ • re ^ 3 en u 3 r f—1 60-O 3 3 rt rt •H Ul * AJ /^ cn •O 3 03 iH en CJ 0 Ul fH -H

VPu* u 3 r 3 •H 3. >^ O 3 ^^ t - O 'o AJ •H = pt: u-l rH O 3 O rt = AJ re * 73 /-^ en p o; 3 r-l > 3 i0H "uH U-l V u -o . cn lAoM ccn 3 o O M iH •H CJ 4-1 Ul ^-' re o iH AJ Z 3 o rt a re 3 o ft re a. 3 AJ r- /~v cn 3 cn 3 O -3 •H 03 3 rt Ul O 60 AJ B re : re .H IH • •3 M /-N tn 3 U 3 3 0 Ul 3. 4J re O O 3 ^-.^ re cr ft cn ^ cn u-l •o re 0 3 60 cn 3 AJ 0 r- O iH Iv r-l U .^4 ^1 v-^ U

so

3 U 3 6C 108 109 (0 z co rt •H c AJ rt rt 3 rH iH 3 3 3. O 0 a 3. Ul AJ /-s z en 3 •1 iH #-s 60 CO 3 3 rt iH PH O Ul Ul AJ -H U TS 3 S 0 P.'H ^P0* N-Po' ^ ^ •H cn >i re 3 60 U 3 u 3 o 03 AJ •-M r ej Ul o O Ul u-l 4J re re 3 AJ CJ re : •3 AJ /#^^ •H cn 3 "3 Ul 3 u- O H c re O "H •3 M 3 Ul 3 o a AJ o CJ v-' re ft z AJ -oH tn oi 3 •H rJ re 3 60 o re = M •> M /~v cn U 3 o --^ AJ O O Ul re "^ • ft o cn re i^ "O CJ O 3 CJ cn 3 AJ 0 ?^ O <-! rH O U_ CU >w O

3 Ul 3 60 110