Volume 65 — Issue 3 (Sept 2000)

Noteworthy Collections Maryland, District of Columbia, Georgia, and South Carolina

This large format (21 29 cm) coffee-table book includes a foreword by the late W.H. Wagner, Jr., a map of the region covered, lists of species by flower color, an illustrated glossary, and an index to common and scientific names.

For more than 3 decades, John Kartesz and his talented staff have pursued the idealistic goal to have no less than all of the information on all of the North American vascular flora available in a single work. Already well-known for his major 2 volume work A Synonymized Checklist of the Vascular Flora of the United States, Canada, and Greenland, Dr. Kartesz and his colleagues have entered the electronic medium with a blockbuster, the only comprehensive source for the nomenclature and taxonomy for all known native and naturalized vascular plants (along with their synonyms, nearly 75,000 names) as well as distribution data and other useful information for the approximately 28,000 named taxa in North America north of Mexico (including Puerto Rico and Hawaii!). There is something for everybody in this Synthesis.

Two species of the water fern Salvinia (S. minima Baker and S. molesta D. S. Mitchell) are known from Alabama. Members of this genus have often been used as aquarium (Muehlberg 1980) and water garden plants and have been distributed through both trades. Salvinia is a floating aquatic fern with stiff, erect hairs on the adaxial leaf surface (surface away from the water), each hair branched distally into four. These hair branches are taxonomic characteristics used to distinguish the Alabama species. Those of S. minima are separate distally, whereas those of S. molesta are connate distally, the latter appearing as a birdcage sitting on an erect pedestal.

Eleven species and one subspecies are reported as new or noteworthy to the flora of Kentucky. Carex cherokeensis Schweintz, Carex reniformis (L. Bailey) Small, and Carex seorsa Howe are reported for the first time. Significant increases in distribution are reported for Carex abscondita Mackenzie and Carex socialis Mohlenbrock & Schwegman. Additional records and/or updates of historical records include Carex aestivalis M. A. Curtis, Carex alata Torrey, Carex appalachica Webber & Ball, and Carex leptonervia (Fernald) Fernald. Previously reported but without cited vouchers, the occurrence of Carex atlantica L. Bailey subsp. capillacea (L.Bailey) Reznicek, Carex crebriflora Wiegand, and Carex longii Mackenzie are now verified.

Lotus unifoliatus var. helleri (Carolina Birdsfoot Trefoil), is a candidate rare taxon of the Piedmont in North Carolina. The distribution of individuals in a Rowan County population was clumped. The abundance of individuals, their height, cover, and fruit production were negatively related with occurrences of Dichanthelium scoparium, Panicum anceps, and Liquidambar styraciflua. A field experiment indicated no significant effect of opening size in grassy vegetation on trefoil seed germination, survivorship, average height, and fruit production. A field clipping study suggested that roadside mowing prior to flower initiation may not reduce survivorship or fruit production to levels below those of unmowed plants.

In vitro symbiotic seed germination of the yellow fringeless-orchid, Platanthera integra (Nuttall) Gray ex Beck, is reported. Seeds of P. integra collected from the Green Swamp (Brunswick, County, North Carolina) were inoculated with mycorrhizal fungi (Epulorhiza spp.) isolated from the root-like organs of three southeastern orchids: Platanthera ciliaris (L.) Lindley, P. integrilabia (Correll) Luer, P. integra. All fungi promoted seed germination, and leaf-bearing seedlings were obtained using the fungus from P. integrilabia. Seeds exposed to prolonged (1 and 2 hr) scarification followed by white light pretreatment (12 hr: 12 hr; L:D) yielded a higher percentage of leafless seedlings (protocorms) compared to standard techniques. We advocate the widespread preservation of existing orchids and their habitats in order to safeguard mycor- rhizal fungi for use in conservation.

Betsch Fen is a 14 ha fen in south central Ohio and is among the largest and least disturbed periglacial fens of the region. Of the 107 taxa of vascular plants recorded during surveys conducted in 1994-96 only five were non-native, and those five were found predominantly in the riparian forest which bordered the fen proper. Significant populations of eight state-listed species were present (Carex tenera, Carex trichocarpa, Filipendula rubra, Gentiana procera, Parnassia glauca, Potentilla fruticosa, Sanguisorba canadensis, and Solidago ohioensis) as well as populations of the rare spotted turtle (Clemmys guttata) and the Baltimore checkerspot butterfly (Euphydryas phaeton). A narrow band of riparian forest bordering a stream divides Betsch fen into two fen areas. The northern fen was covered by sedge meadow in which Carex stricta was the dominant. In contrast, the southern fen included areas of open marl flat typified by Juncus brachycephalus, Rhynchospora capillacea, and Scirpus acutus, sedge meadow, shrub meadow dominated by Salix exigua and various fen indicator herbs, and distinct, monospecific patches of Acorus calamus. Ground water alkalinity varied among community types with areas dominated by Acorus calamus having the greatest alkalinity and the bordering forest the lowest. Analysis of a 56 year record of aerial photos indicates that the northern fen has been stable in size whereas the southern fen has expanded since the site was acquired by The Nature Conservancy. The information presented here supplies a baseline for monitoring the efficacy of the management efforts ongoing in this unique remnant.

The goals of this study were to document natural hybridization between Rhododendron periclymenoides and R. atlanticum and to assess its significance relative to herbivory by Pyrrhalta rufosanguinea, a leaf beetle believed to be monophagous for R. periclymenoides. Populations of the Rhododendron species and a putative hybrid swarm were compared using a mixture of quantitative morphological and micro-molecular characters. Herbivory in parental and hybrid populations was estimated in cafeteria style host-choice experiments. Principal components analysis and discriminant analysis suggested bidirectional introgression in the hybrid population. Feeding levels were significantly higher for putative introgressants to R. periclymenoides than for introgressants to R. atlanticum. In the hybrid population, percent leaf area eaten by the beetles was positively correlated with leaf size and concentrations of the flavonoid asebotin and its aglycone, but negatively correlated with glandular trichome density and the concentration of myr- icentin 3-0-rhamnoside. Two hypotheses regarding the evolutionary significance of natural hybridization between the two Rhododendron species are proposed: 1) introgression from R. atlanticum to R. periclymenoides may result in greater resistance of R. periclymenoides to P. rufosanguinea; 2) gene flow from R. periclymenoides to R. atlanticum may allow P. rufosanguinea to become adapted to R. atlanticum.