Date of Award:

5-1972

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Plants, Soils, and Climate

Department name when degree awarded

Botany

Committee Chair(s)

Arthur H. Holmgren

Committee

Arthur H. Holmgren

Committee

William S. Boyle

Committee

Douglas R. Dewey

Committee

Lamar Anderson

Abstract

Two single-spikelet species, including three varieties, of naturally occurring wild-ryes of the genus Elymus native to the Rocky Mountain and Intermountain West were investigated using morphological, anatomical, ecological, and cytogenetical methods to determine their biosystematic relationships.

One species, Elymus ambiguus Vasey and Scribn., was found to be a distinct species without any recognizable varieties. This species had been previously recognized with three varieties.

One taxon, Elymus salina (C. L. Hitchc.) E. Jensen, often considered a variety of Elymus ambiguus, was found to be a distinct species. It shared features with both Elymus ambiguus and Elymus salina but was sufficiently dated to prevent its inclusion as a varietal form of either of them.

Another taxon, Elymus salina M. E. Jones, was found to exist at two levels, tetraploid and octoploid. One population at the tetraploid level, from southwestern Wyoming, had previously been misnamed Elymus ambiguus var. strigosus. It differed from the type specimen of Elymus strigosus and upon examination was observed to be extremely similar to Elymus salina. It differed from Elymus salina in chromosome number, 2n=28 versus 2n=56, and in pubescence of the lemmas, but in all other aspects was a good member of Elymus salina.

Detailed morphological and anatomical information is given for all the species.

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