Volume 59 – Issue 2 (Jun 1994)

Recent advances in technology and quantitative analysis have revitalized the field of plant reproductive ecology and evolution. Some of the questions discussed in this volume based on a 1991 conference held in Athens, Georgia, include: What forces determine the evolution of plant mating systems? Why is it important to botanists and geneticists, but for different reasons, to understand that inbreeding depression is critical in determining when selfing will evolve? How is fitness in plants transmitted-directly or by kin selection? How are disabled (sterile) seeds and pollen examples of social behavior in plants?

The effects of induced plant injury on leaf lobation of red mulberry (Morus rubra L.) were studied in 1990, 1991, and 1992 at Bowling Green, Kentucky. Injury treatments consisted of complete defoliation of sprouts and saplings and trunk and branch removal from saplings. Pre- and post-injury lobation means were compared. In general, leaf defoliation (only) resulted in new flushes of leaves that were less lobed, whereas leaf defoliation plus stem and branch removal resulted in the production of adventitious branches with new flushes of leaves that were more lobed. This leaf lobation response to plant injury was interpreted as being of adaptive value to the plant. The resulting stress morphology was attributed to phenotypic plasticity of leaf lobation.

Alnus serrulata (Ait.) Willd., an alder species endemic to eastern North America, was investigated for its ability to form ectomycorrhizae with six species of fungi in vitro. Only Hebeloma cf. crustuliniforme and Paxillus involutus formed mycorrhizal sheaths with hartig nets. These two species are associated with Alnus in nature. Two other associated fungi, Alpova diplophloeus and Paxillus filamentosus, did not form ectomycorrhizae vitro. Two broad host range fungi, Cenococcum geophilum and Pisolithus tinctorius, not form ectomycorrhizae with A. serrulata. These results support the hypothesis that genus Alnus is highly specific in its mycorrhizal

Samples (n = 56) of six species of bryophytes were collected from eight sites in Eastern Kentucky and analyzed for Cu, Cr, Fe, Mn and Zn via neutron activation analysis. The concentrations of copper and iron in Eastern Kentucky moss tissue were considerably higher than at other North American sites. Concentrations of zinc, manganese, and chromium fell well within the reported values for other North American locations. Iron was found in Kentucky moss tissues in concentrations of 103 ppm. Copper and manganese were present in concentrations of 102 ppm. Zinc was present at concentrations of 101 ppm and chromium was present at levels of less than 10 ppm dry weight.

Cross Creeks National Wildlife Refuge is a 3,588 ha (8,862 acre) unit owned and managed by the U.S. Department of Interior, Fish and Wildlife Service, to provide food, water, and cover for resident, migratory, and wintering waterfowl. It was established in 1962 and extends for 16.09 river km (10 river miles) on both sides of the Cumberland River (Lake Barkley) between Dover and Cumberland City, Stewart County, Tennessee. Most of the refuge is on river bottomland that was agricultural prior to 1962. Management practices include moist-soil crops for wildlife, agricultural production, successional fields, and 16 managed pools where dams, levees, and floodgates allow water level manipulation. The Cumberland River and five major tributaries are permanently impounded with seasonal variations in pool levels. Various wetland habitat and community types occur, including marshes, swamps, dewatered zones, bottomland forests, and permanent deep water. The goal of the project was to conduct a floristic survey of the refuge, exclusive of a few peripheral uplands. Seventy-eight collecting trips between July 1990 and June 1992 yielded 633 taxa representing 367 genera and 116 families. Seven of these taxa are state and/or federally listed.

Vascular plants of high-elevation cliffs and rock outcrops were sampled on 42 peaks in the Southern Appalachians. Species found were predominantly native, summer-flowering, herbaceous perennials. Species endemic to the Southern and Central Appalachians comprise over 25% of the total flora; species restricted to eastern North America include nearly 50% of the flora. The diversity of biogeographic affinities shows that the northern alpine element (those species found above treeline in the Northern Appalachians) is only a small subset of the total flora. At least 17% of species were likely components of the Pleistocene alpine flora. An annotated checklist of the 288 species is provided.