Life Sciences Commons^™

Noteworthy Collections: Virginia, W. John Hayden

Biology Faculty Publications

The above collections represent the second record for the state of Virginia, and may well establish the northernmost station for the species in the eastern United States. According to B.L. Lipscomb (Sida 8:320-327. 1980), this Old World weed is spreading throughout the warmer regions of North America. The only previous record of the species from the state is a Fernald specimen from Owl Creek in Virginia Beach. R.W. Tyndall, who found the species in northeastern North Carolina, was unable in 1978 to locate the plant at Fernald's Virginia Beach locality (Castanea 48:277-280. 1983). The Amelia County plants occur in two …

Flora Of Richmond National Battlefield Park, Virginia, W. John Hayden, Melanie Lynn Haskins, Miles F. Johnson, James M. Gardner

Biology Faculty Publications

An inventory of the vascular flora of nine of eleven units of Richmond National Battlefield Park was compiled from 1985 to 1987. Each site was visited during the growing season in two to four week intervals; plant species were identified and recorded in the field and/or collected for later study. A total of 761 different species were identified in the surveyed units, and 2487 individual records of species per particular park unit were noted. Twenty-three percent of the flora consists of exotic species, largely from Eurasia. Voucher specimens are housed in the herbaria of the University of Richmond and Virginia …

Hands-On Activities That Relate Mendelian Genetics To Cell-Division, Heather Mckean, Linda S. Gibson

Biology Faculty Publications

No abstract provided.

Woody-Plant Succession In An Eastern Nebraska Bluff Forest, Douglas E. Borland, Thomas B. Bragg, David M. Sutherland

Biology Faculty Publications

Woody plant composition of ridgetop old-fields abandoned at various times since 1800 suggest a successional pattern for an eastern Nebraska bluff forest. Sites abandoned for 24 years were dominated by elm (Ulmus spp.) and rough-leaved dogwood (Comus drummondii). Other sites, abandoned for76 years, were dominated by bitternut hickory (Cwya cordijormis), American linden (Tilia americana), and hop-hombeam (Ostrya virginiana), and those abandoned for 186 years were predominantly bur oak (Quercus macrocarpa) and hop-hornbeam. Based on species importance values, we conclude that the composition of this forest is still changing.

An Annotated List Of The Vascular Plants Of Keith County, Nebraska, David M. Sutherland, Steven B. Rolfsmeier

Biology Faculty Publications

This study provides an annotated list of the vascular plants known to exist outside of cultivation in Keith County, Nebraska. Listed are a total of 599 species, subspecies and varieties belonging to 302 genera of 87 families. Notes are included about frequency and habitat for each of the taxa. 264 (44.1 %) of the taxa listed were previously unreported for Keith County. Additionally, the paper discusses vegetation regions in the county and gives information in tabular form about numbers of the flora in different taxa, the ten largest families, numbers of taxa of different growth habits, and numbers of taxa …

Effect Of Conidia Germination On Infection Of Brown Planthopper (Bph) By Insect Fungi, M. C. Rombach, R. M. Aguda, Donald W. Roberts

Biology Faculty Publications

Conidia of insect fungi actively invade BPH [brown planthopper]. After a conidium lands on the insect cuticle, germination takes about 8 to 16 h, depending on the temperature and relative humidity. After the germination, tuber is formed, the conidium produces specific chitinase enzymes to dissolve the insect cuticle. This allows the fungus to enter the insect body cavity, where further fungus growth occurs. At the end of the infection cycle, the mycelium sporulates on the outside of the insect. Conidia produced on the cadaver can infect healthy BPH initiating epizootics of the fungus. To test infection, 50 adult alate BPH …

Ontogeny Of The Cotyledonary Region Of Chamaesyce Maculata (Euphorbiaceae), W. John Hayden

Biology Faculty Publications

Development of the cotyledonary region in Chamaesyce maculata is described from germination of the seed through formation of the dense mat of branches which characterize this common weed. The cotyledonary node is trilacunar with split-lateral traces. Epicotyl development is limited to a pair ofleaves ("V-leaves") inserted directly above and decussate to the cotyledons. The two V-leaves are also vascularized by three traces and insertion of these traces relative to the vasculature at the immediately subjacent cotyledonary node is asymmetrical; four of the six V-leaf traces arise on one side of the intercotyledonary plane and two arise on the opposite side. …

Histology Of The Ovaries And Fat Bodies Of Chthonerpeton Indistinctum, Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

Histological analysis revealed three different stages in the development of ovarian follicles of Chthonerpeton indistinctum. These stages are identified by (1) location of the oocyte in the ovary wall, (2) oocyte morphology and staining characteristics, (3) development of the zona pellucida, and (4) organization of the follicular layer. Atretic follicles and corpora lutea also were found. Fat bodies are composed of well-developed adipose tissue.

Diseases And Plant Population Biology, Nancy J. Huntly, R Inouye

Biology Faculty Publications

No abstract provided.

New And Corrected Floristic Records For Nebraska, Steven B. Rolfsmeier, Robert B. Kaul, Marjorie M. Garabrandt, David M. Sutherland

Biology Faculty Publications

New distributional data are given for 54 species of vascular plants in Nebraska. Twenty are newly recorded for the State. 23 are shown to be more widespread than was previously known, seven are shown to have more restricted ranges than previously reported. the records of one species attributed to the State are shown to be based on misidentifications. and the presence in the State of three species collected long ago is confirmed by recent collections.

Historical Notes On Collections And Taxonomy Of Penstemon Haydenii S. Wats. (Blowout Penstemon), Nebraska's Only Endemic Plant Species, David M. Sutherland

Biology Faculty Publications

Penstemon haydenii was originally described in 1891 by Sereno Watson and was named for its first collector, the geologist and explorer Ferdinand V. Hayden, who probably collected it in the late summer of 1857 in the" Sand Hills of Loup Fork," Nebraska. The Hayden specimen which Watson saw in the Gray Herbarium at Harvard University had evidently been labeled with an incorrect location. Watson did not base his description on that early specimen but upon a more complete specimen, also in the Gray Herbarium, taken by Herbert J. Webber in Thomas County in 1891; so the Webber specimen, not the …

Bird Territories: A Key To Understanding Bird Behavior, Robert A. Askins

Biology Faculty Publications

No abstract provided.

The Identity Of The Genus Neowawraea (Euphorbiaceae), W. John Hayden

Biology Faculty Publications

On the basis of newly acquired morphological evidence gathered in the course of floristic studies, the monotypic genus Neowawraea Rock is now recognized as a species of Flueggea Willd. and is renamed F. neowawraea W. J. Hayden. Taxonomic documentation presented for F. neowawraea includes an expanded morphological description, a map showing its widely scattered distribution in the Hawaiian Islands to which the species is endemic, and discussions of type specimens, common names, and its extreme rarity. The combination of flowers in pedicellate axillary clusters, the lobed staminate disk, pistillode, extrorse anthers, hemitropous ovules, and, especially, the smoothish dry seeds with …

Effect Of Changes In Regional Forest Abundance On The Decline And Recovery Of A Forest Bird Community, Robert A. Askins, Margarett J. Philbrick

Biology Faculty Publications

Bird populations were monitored for 32 years in a 23-ha tract of hemlock-hardwood forest. Between 1953 and 1976 the total abundance of long-distance migrants declined significantly and four species disappeared, but after 1976 both the total abundance and the number of species increased. Multiple regression analysis shows that the abundance of long-distance migrants was negatively related to abundance of bird species characteristic of suburban habitats and positively related to the amount of forest within 2 km of the study area. The decline in long-distance migrants before 1976 occurred when suburban species were increasing and nearby forest was destroyed. The increase …

Anatomy And Affinities Of Penthorum, Melanie Lynn Haskins, W. John Hayden

Biology Faculty Publications

The genus Penthorum L. consists of two species of perennial herbs, P. sedoides of eastern North America and P. chinense of eastern Asia. Penthorum has long been considered intermediate between Crassulaceae and Saxifragaceae. An anatomical study of both species was undertaken to contribute to a better understanding of the relationships of these plants. Prominent anatomical features of Penthorum include: an aerenchymatous cortex and closely-spaced collateral vascular bundles of stems; one-trace unilacunar nodes; brochidodromous venation, rosoid teeth bearing hydathodes, and anomocytic stomata of leaves; angular vessel elements with many-barred scalariform perforation plates and alternate to scattered intervascular pits; thin-walled nonseptate fiber-tracheids; …

Influence Of Rufuging Consumers (Pikas: Ochotona Princeps) On Subalpine Meadow Vegetation, Nancy J. Huntly

Biology Faculty Publications

Talus slopes in western North America frequently are bordered by vegetation that differs in biomass, cover, height, and species composition from vegetation located farther from talus. These areas are grazed by pikas (Ochotona princess, which nest in that talus. Foraging theory predicts that pikas will produce a gradient of grazing pressure, which could produce the observed vegetational zonation. In a subalpine meadow in west-central Colorado, pikas produced the predicted gradient of grazing pressure, along which plant groups varied clinally in abundance. The effects of pikas on talus-border vegetation were tested by excluding pikas from small plots at several distances from …

Old-Field Succession On A Minnesota Sand Plain, R S. Inouye, Nancy J. Huntly, D Tilman, J R. Tester, M Stillwell, K C. Zinnel

Biology Faculty Publications

Vegetation and soils were sampled in 22 old fields ranging in age from 1 to 56 yr since abandonment. Soil nitrogen concentration increased significantly with field age. Vegetation cover, total aboveground plant biomass, and litter cover increased significantly with soil nitrogen. Light penetration to the soil surface was negatively correlated with total plant biomass. Field age and soil nitrogen concentration were used as independent variables in simple regression and partial correlation analyses to determine the relative importance of such time—dependent processes as dispersals vs. the availability of a limiting resource (nitrogen) as predictors of patterns in species richness or the …

New And Corrected Records Of The Flora Of Nebraska, Steven B. Rolfsmeier, Robert B. Kaul, David M. Sutherland

Biology Faculty Publications

New distributional data are provided for 27 species of vascular plants in Nebraska, eight newly recorded as growing wild in the State. The record of one species previously attributed to the State is shown to be based upon misidentified specimens, the range of another is shown to be much more restricted in Nebraska than previously reported, and nomenclature is corrected for two species.

Spermatogenesis And Histology Of The Testes Of The Caecilian, Chthonerpeton Indistinctum, Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

Macroscopically, the testes of Chthonerpeton indistinctum consist of a series of oval lobes. The number and size of lobes is variable in Chthonerpeton indistinctum. Histologically, the testes are divided into structural units, locules separated by septa of connective tissue. Inside of each locule spermatogenesis takes place in cysts of germinal cells that divide synchronically. Chthonerpeton indistinctum is divided chronologically into four stages of development based on the shape of the nuclei of the spermatids and their arrangement in the cyst: (1) round, (2) kidney shaped, (3) attenuate, and (4) bouquet arrangement.

Genetic Engineering, W. John Hayden

Biology Faculty Publications

Why do so many biologists express so little concern for biology as a whole and such contempt for fields other than their own? The current debate on release of genetically engineered organisms into the environment, specifically, J. E. Fox's recent reply (Letters, 18 Oct., p. 237) to an earlier letter by R. K. Colwell et al. (12 July, p. 111), offers a case in point.

Nebraska Plant Distribution, David M. Sutherland, Robert B. Kaul

Biology Faculty Publications

Distribution notes based on recent collections and herbarium work are provided for 46 Nebraska plant taxa, including 43 flowering plants, two ferns, and one liverwort. The list includes several plants that are new to the State and provides range extensions within the State for many others. Several previously- published distribution records believed to be erroneous are also discussed.

Repair-Deficient Xeroderma Pigmentosum Cells Made Uv Light Resistant By Fusion With X-Ray-Inactivated Chinese Hamster Cells, Deneb Karentz, James E. Cleaver

Biology Faculty Publications

Xeroderma pigmentosum (XP) is an autosomal recessive human disease, characterized by an extreme sensitivity to sunlight, caused by the inability of cells to repair UV light-induced damage to DNA. Cell fusion was used to transfer fragments of Chinese hamster ovary (CHO) chromosomes into XP cells. The hybrid cells exhibited UV resistance and DNA repair characteristics comparable to those expressed by CHO cells, and their DNA had greater homology with CHO DNA than did the DNA from XP cells. Control experiments consisted of fusion of irradiated and unirradiated XP cells and repeated exposure of unfused XP cells to UV doses used …

Eryngium Prostratum In Central Virginia, W. John Hayden

Biology Faculty Publications

While visiting Pocahontas State Park in Chesterfield County, Virginia during the fall of 1984, an unfamiliar blue-flowered plant was observed growing near the upper reaches of Swift Creek Lake. This proved to be Eryngium prostratum Nuttall ex DC., a species common near bodies of water in the southeast U.S. While several standard floras include Virginia in the distribution of this plant (Fernald 1950, Gleason 1952, Gleason & Cronquist 1963, Radford et al 1968, Godfrey & Wooten 1981), the only counties for which it is recorded in Harvill et al (1981) are along the extreme southern border of the state, i.e., …

The Effects Of Mute Swans On Native Waterfowl, Maria O'Brien, Robert A. Askins

Biology Faculty Publications

No abstract provided.

Consumption Of Aquatic Plants By The West Indian Manatee, Kay Etheridge, G. B. Rathbun, J. A. Powell, H. I. Kochman

Biology Faculty Publications

Because manatees (Trichechus manatus) are large aquatic herbivores they have often been considered as potential control agents for aquatic plants. Several problems are associated with this concept, and a major one has been the gap in knowledge concerning food consumption rates of manatees. We estimated food consumption by measuring chews per unit time, chews per amount of food consumed, and time spent chewing food. Data were collected on captive manatees of various sizes and used to construct regression equations that predict consumption rates based on body size. Time budget data were obtained by radiotelemetry of free-ranging animals. Estimates of …

Gametogenesis En Chthonerpeton Indistinctum (Gymnophiona: Typhlonectidae), Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

RESUMEN:

Histológicamente, las gónadas de Chthonerpeton indistinctum son similares a las ya descritas para otras especies del orden Gymnophiona. Los lóbulos testiculares se hallan compartimentados en unidades estructurales denominadas lóculos. La espermatogénesis ocurre en cistos sincrónicos de células germinales. Durante la espermiogénesis se identifican cuatro estados consecutivos de desarrollo: 1) cistos de espermátidas redondeadas; 2) cistos de espermátidas arrifionadas; 3) cistos de espermátidas bastoniformes y 4) espermátidas en ramillete.

El análisis histológico de los ovarios mostró la presencia de tres estados en la maduración de los folículos ováricos. Estas etapas pueden ser identificadas de acuerdo a: 1) ubicación del folículo …

Morfología Y Funciones Del Conducto De Müller De Chthonerpeton Indistinctum (Reinhardt Y Lutken, 1862) (Amphibia: Gymnophiona) En Relación Con Los Mecanismos Reproductivos De La Especie, Nibia Berois, Rafael O. De Sá

Biology Faculty Publications

El orden Gymnophiona comprende anfibios ápodos, ciegos, de hábitos cavícolas y acuáticos. Como consecuencia de estos hábitos resulta muy difícil su colecta, lo cual redunda en un escaso conocimiento de la biología del orden y sobre las relaciones filogenéticas del mismo.

Una de las características más particulares del grupo se refiere a la modalidad reproductora, ya que aproximadamente el 50% de las especies presentan viviparidad y la totalidad de ellas tienen fecundación interna. Es por esta razón que el estudio del aparato reproductor ha sido encarado por diversos autores, en especial por Wake (1968, J. Morphol. 126: 291) con una …

Estructura Del Ovario De Chthonerpeton Indistinctum (Reinhardt Y Lutken, 1862) (Amphibia: Gymnophiona) Durante La Gestación, Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

La morfología e histología del ovario para varias especies del orden Gymnophiona ha sido reportada por Wake (1968, J. Morphol. 126, 291) y para C. indistinctum por los autores (1984, XXIV Reunión de Comunicaciones, Soc. Zool. Uruguay).

Continuando con los estudios sobre el aparato genital de esta especie vivípara, se presenta ahora la estructura del ovario durante la gestación.

Se procesaron con fines histológicos, ovarios de dos hembras grávidas colectadas en las costas de los Dep. Montevideo y San José en abril, 1983. El número de ejemplares trabajados es muy reducido dado lo difícil que resulta su colecta …

Seasonal Responses Of Filtration Rates To Temperature, Oxygen Availability, And Particle Concentration Of The Freshwater Clam, Musculium Partumeium (Say), Albert J. Burky, Richard B. Benjamin, Denis G. Conover, Jennifer Detrick

Biology Faculty Publications

Seasonal filtration rates of a pond population of the freshwater pisidiid clam, Musculium par­tumeium (Say), were assessed by measuring the clearance of 2.02 µ.m latex beads from suspension and expressed in terms of FR = a(AFDW}b where FR = filtration rate (ml H20 · hr- 1 ) , AFDW = mg ash-free dry weight of a whole clam and "a" and "b" are constants. The a-values ( = FR of a 1-mg AFDW clam} vary seasonally with the highest rates corresponding to periods of maximum growth and reproduction in the spring and fall. Changes in "b" reflect the influence of …

University Of Richmond Herbarium, W. John Hayden

Biology Faculty Publications

The Department of Biology at the University of Richmond, Richmond, Virginia, maintains an herbarium of approximately 15,000 specimens. Although recently assigned the acronym URV, this collection has not yet been included in Index Herbariorum and, consequently, few botanists outside of Virginia are aware of its existence. This note provides a brief account of the history of URV, a summary of its contents, and a short bibliography of works pertaining to the collection.