Campus Access Only

All rights reserved. This publication is intended for use solely by faculty, students, and staff of University of the Pacific. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, now known or later developed, including but not limited to photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author or the publisher.

Date of Award

1983

Document Type

Thesis - Pacific Access Restricted

Degree Name

Master of Science (M.S.)

Department

Graduate School

First Advisor

Dale McNeal

First Committee Member

Alice S. Hunter

Second Committee Member

Steven C. Anderson

Abstract

The taxa of the Allium obtusum complex were examined morphologically, chromosomally, and with the use of the scanning electron microscope, Additional field studies included ultraviolet photography, caging experiments, and collection of insect visitors.

Based on the cumulative information gathered during this investigation, of the 7 taxa previously proposed in this complex, 4 are considered to be valid: A. cratericola, A. obtusum, A. tribracteatum, and A. yosemitense, A new variety of A. 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 A. cratericola which was found to be tetraploid (2n=28).

Scanning electron microscope studies demonstrated the usefulness of outer bulb coat reticulation as a taxonomic character in differentiating between the species of the complex.

Preliminary data collected during field investigations 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 flowers 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 represents a distinct and homogeneous assemblage of interrelated species and varieties.

Pages

95

To access this thesis/dissertation you must have a valid pacific.edu email address and log-in to Scholarly Commons.

Find in PacificSearch

Share

COinS