Date of Award

1999

Degree Name

Biological Sciences

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Dan Evans

Second Advisor

Leonard J. Deutsch

Abstract

The origin of Carex x deamii Herm. has been in question ever since it was named to science in 1938. Collections of the hybrid have always been associated with C. shortiana Dewey and either C. typhina Michx. or C. squarrosa L.. C. typhina and C. squarrosa are closely related taxa (Section Squarrosae) and often are morphologically similar. Because of this similarity, determining the correct parental species to the hybrid has been extremely difficult. It is known that the hybrid is sterile and only reproduces asexually. Pollen was analyzed to ascertain the viability of all four taxa. This study utilizes both macro and micro morphological characters in a numerical taxonomic analysis to determine the parental species of C. x deamii. Macromorphological characters include vegetative and reproductive parts. Micromorphological characters focused on surface features of leaves, perigynia, and pistillate scales. In addition, achenes were analyzed for distinctive features and X-Ray analysis was done on all plant parts to determine the presence and distribution of silica for these taxa. Data was analyzed using SAS and HYWIN (Hypothesizing hybrids using Weighted Intermediacy). Principal Component Analysis (PCA) and Canonical Discriminant Analysis (CDA) were done using the SAS program. The three putative parental species were all had ~90 % viable pollen. The hybrid, while sterile, did have 2.3 % of its pollen viable. All statistical analyses showed C. shortiana to be the most likely parent to the hybrid. Likewise, all analyses showed C. typhina to be the other parent species. The most important characters in both macro and micro morphological analysis were perigynia features (perigynium beak length in macromorphological analysis and perigynium epidermal cell length/width ratio in the micromorphological analysis.

Subject(s)

Carex – Morphology.

Plant species.

Hybridization.

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