Plant Sciences Commons^™

Scanning Electron Microscopy, Histological, And Tissue Culture Studies Of Powdery Mildews Infecting Dogwoods, Leigh Ann Klein

Masters Theses

Powdery mildew has become a common and widespread foliar disease of dogwoods. Microsphaera pulchra Cooke and Peck, and Phyllactinia guttata (Wallr.: Fr.) Lev. are two causal agents of powdery mildew on dogwood species in eastern North America. A clear understanding of the host-pathogen relationship between these fungi and their host must be obtained to advance research in disease management and resistance breeding.

A necessary step in studying a disease is to identify the causal agent. Leaves of C. florida 'Cherokee Sunset' and C. amomum (silky dogwood) were observed under a compound microscope to determine causal agents of powdery mildew based …

The Vascular Flora Of The Upper Clinch River In Claiborne, Grainger, And Hancock Counties, Tennessee, Bobby Christopher Bullington

Masters Theses

The vascular flora along a portion of the Upper Clinch River (UCR) in Claiborne, Grainger, and Hancock Counties, Tennessee was inventoried for two full growing seasons in 1994 and 1995. A total of 526 species and lesser taxa in 108 families and 338 genera were documented. Three hundred and twenty-six taxa were determined to be county records. Six taxa are state listed as threatened or special concern species in Tennessee.

Distributions of the taxa indicate a strong northern extraneous influence on the flora. However, intraneous elements still represent the single largest category. Northern taxa comprise almost 52% of the total …

Biological Species Concepts In Eastern North American Populations Of Lentinellus Ursinus, Andrew N. Miller

Masters Theses

As part of a biosystematic study of the Lentinellus ursinus species complex, field and herbarium specimens from North America, Central America, and Europe were examined. Single basidiospore isolates from basidiomata collected in Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Tennessee, North Carolina, Wisconsin, Costa Rica, and Austria were crossed in all possible combinations to determine the mating system operating in each population. All populations exhibited bifactorial or tetrapolar mating systems. Tester strains were then crossed to identify intercompatible populations and to determine if morphological species in the L. ursinus species complex are congruent with biological species. Three biological species were recognized …

A Study Of The Lichens At Rocky Branch Nature Preserve, Clark County, Illinois, Eric B. Grunder

Masters Theses

In 1971, a graduate student at Eastern Illinois University, James E. Wiedman, studied the lichen flora of Rocky Branch Nature Preserve, Clark County, Illinois. During his study he collected, identified, and recorded a total of 64 lichen species. Since 1971, Rocky Branch Nature Preserve has experienced a dramatic increase in use by people and a concomittant decline in the quality of lichen habitats. In order to assess the decline of suitable lichen habitats and the reduction of lichen species a second study of the lichens at Rocky Branch Nature Preserve was undertaken. As part of this study, ten habitat sites …

Environmental Requirements For Sporocarp Germination In Marsileaceae, Kevin J. Kruep

Masters Theses

Experiments were conducted on sporocarps of Marsilea quadrifolia L. to determine whether temperature had any influence on the length of the reproductive period and initial sperm emergence from microgametophytes. Data were then compared to results of similar studies undertaken with the species M. vestita Hooker and Greville to determine whether there was any variation between them. A slight variation was recorded, ranging from 1 to 1.5 hours for initial emergence.

An additional set of experiments was performed with 58 year old sporocarps and approximately two-year-old sporocarps of M. quadrifolia. A difference of 2-6.5 hours for initial sperm emergence occurred between …