Master's Theses

Date of Award

Fall 1986

Degree Name

Master of Science (MS)

Department

Biology

Advisor

Joseph R. Thompson

Abstract

A two-year project was initiated in 1984 to determine the distribution of Erioneuron pilosum (Buckl.) Nash (Gramineae) in Ellis County and other parts of Kansas; to describe habitat characteristics associated with the distribution of this grass; to examine macromorphological variations of floral and vegetative characters, both between and within sample sites; to examine micromorphological features of the leaf and lemma surfaces and anatomical features of the leaves. A study region comprised of eleven areas covering approximately 36 square miles of rangeland along both sides of the Saline River (northern Ellis County) approximately 15 miles north of Hays, Kansas, and two smaller regions comprised of one area each located west of Hays (central Ellis County), were examined. The species under study was found only in seven of the study areas on hilltops or gentle slopes of the rolling hills and bluffs overlooking the Saline River, where shallow (immature), rocky, and moderately fine (SiL) soil prevailed. In Kansas, the distribution of E. pilosum appears to be limited to counties in the western half where it commonly has been reported (herbarium information) in localities similar to those of this study. Statistical analyses of measurements of selected vegetative and floral pans indicated the existence of a great deal of macromorphological van at ion among "individuals" within a sample (site). Variation between samples (sites) also was indicated. In addition to slight differences in physical conditions such as moisture and temperature, edaphic factors that influence the availability of nutrients or moisture were likely responsible for the variation between individual s of different areas (geographic variation). Within a particular sample (site), variation was probably a result of slight genetic differences between individuals. The examination in cross section of leaves of fertile culms and surface features of leaves and lemmas revealed features common to Chloridoideae including: costal/intercostal zonation of epidermal cells of the leaves: clavate bicellular microhairs (leaf and lemma); cross- and saddle-shaped silica bodies (frequently dumbbell-shaped in costal zones of the leaves); short cells (silica and cork cells) commonly in rows of rive or more over the veins of leaves; triangular and low, dome-shaped subsidiary cells: papillae (adaxial surface of leaves) and "kranz-type" anatomy. Features observed in specimens of E. pilosum that are less common to members of the subfamily include: leaves with both abaxial and adaxial ribs; a conspicuous midrib; the absence of "girders," which are sometimes associated with vascular bundles of leaves; the presence of stomatal complexes displaying parallel-sided subsidiary cells. An unidentified structure, possibly either a papilla or unicellular microhair, occasionally seen on the abaxial surface of some leaves, may be important taxonomically and warrants further study.

Rights

Copyright 1986 Charlene R. Hillgren

Comments

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