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Lonicera maackii is an invasive Asian shrub naturalized in North America that has negative effects on forest understory vegetation. Aqueous extracts of leaves and roots of this plant have been shown to inhibit germination of several species. In this study, we examined the extent to which field-collected soils conditioned by L. maackii growth, with and without additions of L. maackii extracts, had effects on growth, morphology, and reproduction of Arabidopsis thaliana in a greenhouse setting. We also examined the effects of nutrient addition to the same soils on the performance of A. thaliana, whether plant responses to nutrients varied among L. maackii-conditioned and -unconditioned soils, and whether the effects of L. maackii extracts varied in soils with different histories and fertility. Plants grown in forest soil collected from a site where L. maackii was present grew slower and flowered later than plants grown in an unconditioned soil, but ended up being larger, with more leaves, branches and a higher total seed output. Nutrient addition had a positive effect on performance of A. thaliana, but when nutrients were added with extracts of L. maackii roots and leaves, the positive effects of nutrients were greatly diminished. Inhibiting plant responses to resource opportunities is a potentially important indirect effect of allelochemicals. Where direct effects of extracts on growth were seen, leaf extracts had a greater effect than root extracts. While the most important impacts of L. maackii in the field are undoubtedly due to competition for light and moisture, evidence for allelopathic effects of this plant is growing.
The Matanzas Prairie Nature Preserve is located near Bath, Mason County, Illinois, in the extensive glacial sand deposits associated with the Illinois River. This Preserve contains the only remaining high quality wet-mesic sand prairie, shrub prairie, and sedge meadow associated with the Illinois River sand deposits. The sedge meadow, about 5 ha in size, was dominated by Carex stricta (Importance Value or IV of 66.6 out of 200), Calamagrostis canadensis, and Rosa palustris (both with IV's of 28.3). The wet-mesic sand prairie occurred on slightly higher ground and was dominated by Solidago canadensis (IV of 34.2), Andropogon gerardii (IV of 25.9), Carex stricta (IV of 21.9), Poa pratensis (IV of 18.0), and Euthamia graminifolia (IV of 17.7). Parts of the Preserve were shrub prairie with a ground layer similar to the wet-mesic sand prairie community. A total of 340 species of vascular plants were encountered on the Preserve: 5 fern and fern-allies; 100 monocots; and, 235 dicots. Except for Poa pratensis, which was among the dominant species in the wet-mesic sand prairie and shrub prairie, the 38 exotic species were rarely encountered (11% of the flora). The Floristic Quality Index (including exotic species) for the sedge meadow was 38.80, the wet-mesic sand prairie 43.65, and the shrub prairie 31.76.
The vascular plants of the Berea College Forest (BCF), the oldest managed forest in Kentucky, are presented as an annotated species list. BCF is comprised of 3,380 ha in Madison, Jackson, and Rockcastle counties of east-central Kentucky. Forests and diverse habitats include western mesophytic forest, mixed mesophytic forest, oak-hickory forest, mixed oak-Virginia pine forest, secondary succession areas, wetland habitats, and many anthropogenic-influenced areas. The known vascular plants consist of 1,017 specific and infraspecific taxa, 513 genera, and 139 families. Classification divisions with species are Equisetophyta (2), Lycopodiophyta (4), Polypodiophyta (33), Pinophyta (13), and Magnoliophyta (965). One hundred ninety-six taxa (19.27%) are naturalized, persisting, adventive, or cultivated exotics. The Asteraceae (141), Poaceae (100), Cyperaceae (64), and Fabaceae (56) are the largest families.
A survey of myxomycetes was conducted at three sites within Long Hunter State Park, Davidson County, Tennessee, from May 6 to September 30, 2006. Fruiting bodies that developed on samples of bark and plant debris placed in moist chamber cultures were used to supplement field collections. Results include 207 specimens representing 67 species of myxomycetes in 25 genera. Three species (Arcyria minuta, Licea cf. eleanorae, Licea cf. rugosa) appear to be new reports for the United States and a fourth species (Physarum auriscalpium) is a new report for Tennessee.
Three closely related, midwinter to spring-flowering, mesic species of Zephyranthes (Amaryllidaceae) are endemic to the southeastern United States: Z. atamasca, Z. treatiae, and Z. simpsonii. The taxonomic level of the distinctiveness of Z. treatiae from Z. atamasca is discussed. Based on herbarium, cytological, and field studies, and on Principal Component Analysis and pictorialized scatter diagram analysis, we conclude that all three taxa are distinct at the species level. They are distinguished by differences in relative lengths of floral elements. Illustrations, a distribution map, and a key are provided.