University of the Pacific Scholarly Commons University of the Pacific Theses and Dissertations Graduate School 1983 A comparative study of the Allium obtusum comples William R. Mortola University of the Pacific Follow this and additional works at: https://scholarlycommons.pacific.edu/uop_etds Part of the Life Sciences Commons Recommended Citation Mortola, William R.. (1983). A comparative study of the Allium obtusum comples. University of the Pacific, Thesis. https://scholarlycommons.pacific.edu/uop_etds/2096 This Thesis is brought to you for free and open access by the Graduate School at Scholarly Commons. It has been accepted for inclusion in University of the Pacific Theses and Dissertations by an authorized administrator of Scholarly Commons. For more information, please contact [email protected]. A COMPARATIVE STUDY OF THE ALLIUM OBTUSUM COMPLEX A Thesis Presented to the Faculty of the Graduate School University of the Pacific In Partial Fulfillment of the Requirements for the Degree Master of Science by William R. Mortola May 1983 This dissertation, written and submitted by Willi§m Richard Mortola is approved for recommendation to the Committee on Graduate Studies, University of the Pacific Dean of the School or Department Chairman: Dissertation Committee: Chairman •;=- J i i' ACKNOWLEDGMENTS t4uch gratitude is expressed to Dr, Dale 'II, McNeal for suggesting the problem investigated and for his par­ ticipation and supervision during all phases of this in­ vestigation, To Dr. Alice Hunter I am indebted for her reading of the manuscript and her identification of the insects collected during this study. To Dr, Steve Ander­ son I would like to extend appreciation for his reading of the manuscript and for making valuable suggestions. In addition I would like to extend much gratitude to the following: Dr. Hannah Aase for use of her chromosomal data, Dr. Lee Christianson for aid with the statistical analysis, Dr. Paul Richmond for advice concerning photog­ raphy, and Dr. Robert Smutney of the Classics department for the Latin diagnosis of A. obtusum var, robustum. Also I would like to thank Tom Hathorn for many helpful suggestions and Mona Nahhas for assistance in the typing of this manuscript, Lastly I would like to extend greatful acknow­ ledgement to the curators of the herbaria from which mater­ ial was borrowed during this investigation. Thes~ herbaria are indicated below by the standard abbreviations of Holmgren and Keuken (1974). iii CAS California Academy of Sciences CHSC Chico State University Herbarium CPH University of the Pacific Herbarium DAV University of California Herbarium, Davis DS Dudley Herbarium, Stanford University FSC California State University Herbarium, Fresno GH Grey Herbarium, Harvard University JEPS Jepson Herbarium, University of California, Berkeley MO Missouri Botanical Garden ND University of Notre Dame Herbarium NY New York Botanical Garden POM Pomona College Herbarium RSA Rancho Santa Ana Botanic Garden uc University of California Herbarium, Berkeley UCSB University of California Herbarium, Santa Barbara us United States National Herbarium ws Marion OWnbey Herbarium, Washington State University i iv ABSTRACT The taxa of the Allium obtusum complex were exam­ ined morphologically, chromosomally, and with the use of the scanning electron microscope, Additional field stud­ ies included ultraviolet photography, caging experiments, and collection of insect visitors, Based on the cumulative information gathered dur­ ing this investigation, of the 7 taxa previously proposed in this complex, 4 are considered to be valid: !• ~­ ericola, !• obtusum, !• tribracteatum, and A. yosemitense, A new variety of !· obtusum, var, robustum is described, The base chromosome number among all members of the complex is seven, All species are diploid (2n=14), except for one population of !• cratericola which was found to be tetraploid (2n=28), Scanning electron microscope studies demonstrated the usefulness of outer bulb coat reticulation as a tax­ onomic character in differentiating between the species of the complex. Preliminary data collected during field invest­ - ~ igations suggest that the strong absorption of ultraviolet radiation by all members of the complex relative to their reflecting soils may act as a visual cue to insects whose visual spectrum includes UV, Furthermore, in mature flow- v ers the sexual parts of the inflorescence were found to be reflective under UV, perhaps acting as a guide to foraging insects, Caging experiments revealed that all members of the complex are capable of seed set in the absence of insect visitors. It was found, however, that the relative number of seeds produced was significantly higher among control populations. From the cumulative evidence obtained from these various approaches, supported by morphological resemblances, it can be concluded that the Allium obtusum complex repre­ sents a distinct and homogeneous assemblage of interrelated species and varieties, vi TABLE OF CONTENTS Page ACKNO'IILEDGr1ENTS • • iii ABSTRACT . • • v LIST OF TABLES • • • viii LIST OF FIGURES • • ix INTRODUCTION • • • • • 1 Historical Account • • • • • • • • • • • • • 2 Geographic Distribution • • • •• • • • • • 5 Species Concept •••••••••• • • • • • 5 TAXONOMIC STUDIES • • • 8 JVlaterials and Methods • • • • • • • • • • • 8 Results and Discussion • • • • • • • • • • • • 1 1 POLLINATION STUDIES • • •• • 22 Materials and Methods •• • • • • • • • • • • • 22 28 Results and Discussion • • I I • I • • • • • • TAXONOMIC TREATMENT • • 40 LITERATURE CITED • • 84 ::J ' vii LIST OF TABLES Table Page 1 • Sources of Materials Used in the Field and Laboratory Investigation of the Allium obtusum Complex • • • • • • • , , • • , • • • 10 2. Chromosome Numbers in the Allium obtusum Complex . • • , • • • • • • • • • • • • • • 20 3. List of Insect Visitors to Members of the Allium obtusum Complex • • • • • • • • • • • 25 4. Comparitive Seed Production Between Caged and Uncaged Members of the Allium obtusum Complex • • • • • • • • • • • • • • • 34 viii LIST OF FIGURES Figure Page 1, Scanning Electron Micrograph of the Outer Bulb Coat of A. cratericola •.••••••. , • , • 14 2. Scanning Electron Micrograph of the Outer Bulb Coat of A. ;zosemitense • • • • • • • • • • • • • 14 3. Scanning Electron Micrograph of the Outer Bulb Coat of A. tribracteatum • • • • • • • • • • • • 14 4. Scanning Electron Micrograph of the Outer Bulb Coat of A. obtusum • • • • • • • • • • • • • • • 14 5. Scanning Electron Micrograph of the Seed Coat ·of A. cratericola • • • • • • . • • • • • • • 18 6. Scanning Electron Micrograph of the seed Coat of A. ;zosemitense • • • • • • • • • • • • • • • 18 7. Scanning Electron Micrograph of the Seed Coat of A. tribracteatum • • • • • • • • • • • • • • 18 8. Scanning Electron Micrograph of the Seed Coat of A. obtusum • • • • • • • • • • • • • • • • • 18 9. Cages Used During the Field Investigations • • • 24 1 0. Onions and Their Soils Under Visable Light • • • 29 11 • Comparison of Onions and Their Soils Under (a) Black and Wh:i te Photography Verses (b) Ultra- violet Photography • • • • • • • • • • • • • • 31 12. Close-up of Onions and Their Sexual Parts Under uv Light • • • • • • • • • • • • • • • • • 32 13. ~ mellifera Visiting A. obtusum var. sum . • • • • • • • • • • • • • . • • . 36 14. Incisalia er;zphon Visiting A, obtusum var. obtusum . , .. , . • 36 15. Apis mellifera Visiting&· cratericola •• • 38 ix Figure Page 16. Apis mellifera Visiting A. obtusum var. robustum • • • • •• 7 .. , . , , , , . • • 38 17. Holotype of !• tribracteatum • • • • • • • • • 42 18, A. tribracteatum in the Field • • • • • • • • 44 19, Distribution Map of A. tribracteatum • • • • • 46 20, Neotype of A. obtusum var. obtusum • • • • • • 47 21, A, obtusum var. obtusum in the Field • • • • • 50 22. Distribution Map !• obtusum var. obtusum • , , 52 23. Holotype of !• obtusum var, robustum • • • • • 61 24. A. obtusum var. robustum in the Field • , • • • 63 25. Distribution Map of !• obtusum var. robustum • 65 26, Holotype of !• yosemitense • , , , •• , •• , 68 27, !• yosemi tense in the Field •• , • • • , , , , 70 28, Distribution Map of !• yosemi tense , , , • • • 72 29, Holotype of !• cratericola • • • • • • • • • • 74 30. A. cratericola in the Field • • • • • • • • • • 77 31. Distribution Map of !• cratericola • • • • • 79 X INTRODUCTION The genus Allium traditionally has been placed in the family Liliaceae. Hutchinson (1926), moved Allium from the Liliaceae to the Amaryllidaceae on the basis of inflorescence type. Cronquist (1968) on the other hand, tentatively reduced the Amaryllidaceae including it within the Liliaceae, doubting the validity of separating the two families on the single character of ovary position. More recently Takhtajan (1980) split Allium and a few closely related genera from the Amaryllidaceae and erected the family Alliaceae, which he recognizes as different from - "l the Amaryllidaceae in ovary position. The work of Williams (1975) supports this move and points out that members of Alliaceae are closely related to the Liliaceae but distinct. Differences include the absence of cardiac glycosides and the presence of the odorus allyldisulphides, propy- and vinil-sulfides, and the presence of laticifers, in addition to the differences in inflorescence type. Allium contains approximately 500 species predom­ inantly of Northern Hemisphere distribution (Stearn, 1946). In North America, the genus is represented by about 70 species (OWnbey and Aase, 1955). More than a thousand specific names have