During the period of 1992 to 1994, ten belt transects, each consisting of a series of contiguous 10 × 10 m (100 m²) quadrats, were established and sampled at seven study sites in southwestern Virginia and eastern central West Virginia. Each transect extended from a red spruce-dominated community through the ecotone and into the adjacent hardwood community. In 2004 and 2005, these same transects were resampled in order to assess changes that had occurred. As a general trend, red spruce either maintained its ecological status or increased in number in all size classes, with noticeable expansion into the hardwood community at some study sites.

Tree species composition and structure was determined for an old bottomland hardwood forest located in the Moro Creek Bottoms Natural Area in south-central Arkansas. Diversity for this forest was high with species richness ranging from 33 for the overstory and sapling strata to 26 for the seedling stratum and Shannon-Weiner values of 2.54 to 1.02 for the overstory and seedling strata. Sweetgum (Liquidambar styraciflua L.) and oaks (Quercus spp.) dominated the overstory stratum with 66 percent of the importance values. American hornbeam (Carpinus caroliniana Walter) dominated the midstory and sapling strata with 32 and 42 percent of the importance values. Despite the large tree sizes and ages of several trees, comparison of the forest with models of bottomland hardwood succession and eastern United States old-growth definitions indicate the forest can best be described as old pioneer in transition to changing old growth.

The Iroquois Woods Nature Preserve, located just south of Aroma Park, Kankakee County, is in the Kankakee Sand Area of northeastern Illinois. Three relatively distinct topographic zones exist within the preserve (low terrace, shallow depression, high sand terrace). The forest overstory in all three zones, however, is very similar with most of the same species occurring in each zone, but in different densities. These natural communities are probably due to elevation, distance from the river, soil moisture, and erosion due to flooding events. In the low terrace (mesic sand forest), located near the edge of the Iroquois River channel, Quercus rubra, Tilia americana, Ulmus rubra, Aesculus glabra, and Q. macrocarpa dominate, with the oaks in the larger diameter class. In the shallow depression (wet-mesic sand forest) behind the low terrace Quercus bicolor dominated with 50 stems/ha and accounted for almost half of the total basal area. Tilia americana and U. americana were second and third in importance due to the large number of small diameter individuals. East of the depression was a high sand terrace (dry-mesic sand forest) dominated by Q. alba followed by U. americana, Q. velutina, Prunus serotina, and Q. rubra. This preserve contains one of the few examples of high quality mesic sand forests in the state, but oak regeneration is limited, and shade-tolerant species are becoming more abundant.

A survey of vascular plant species at Gooseberry Island Nature Preserve, a 5.56 ha forested island, was conducted during the 2004 growing season. This study was undertaken to document the composition and structure of the vascular flora and to provide baseline information for land management decisions. A young second growth wet floodplain forest and an old-growth mesic floodplain forest community was quantitatively sampled. The wet floodplain forest community was dominated by Acer saccharinum (silver maple) with some Salix nigra (black willow). The mesic floodplain forest was dominated by Aesculus glabra (Ohio buckeye), Acer saccharum (sugar maple), and Quercus macrocarpa (bur oak). Bur oak, a dominant species in the largest tree size classes, was only a minor element in the lower tree size classes and was absent from the shrub and sapling layers. Historical data from 1977 indicate that in the last 30 years there has been a significant increase in buckeye and sugar maple. A total of 162 species in 126 genera and 62 families were encountered, including 35 taxa near the northern limits of their range.

The 459 ha property that makes up the Warren Wilson College campus (Buncombe County, North Carolina) consists of a variety of forested, wetland, agricultural, and disturbed habitats. A total of 991 specimens of vascular plants were collected during 2007–09 to obtain a vouchered flora of the campus property. These specimens documented 562 species in 341 genera and 113 families. Twenty-two percent of the species are not native to the Appalachian Mountain region. Species present that are tracked by the North Carolina State Plant Conservation Program were Hydrastis canadensis and Panax quinquefolius. Plant community types are described and listed for each associated species.

The phylogeny of the southeastern United States species of Hymenocallis was investigated using 23 ISSR presence/absence characters and 10 qualitative and quantitative morphological characters. Maximum Parsimony (MP) and Neighbor Joining (NJ) analyses with bootstrap replicates were performed in PAUP. The total combined data NJ analysis showed several supported clades with morphological synapomorphies. Hymenocallis choctawensis was sister to H. franklinensis [83% bootstrap (bt) support]; these taxa share the morphological characters of oblanceolate leaves, few ovules and the presence of rhizomes. Hymenocallis coronaria was sister to H. liriosme (63% bt) and these taxa share the morphological feature of a prominent yellow “eye” in the middle of their staminal cups and both reproduce asexually by offsets rather than by rhizomes. Hymenocallis godfreyi H. rotata H. tridentata formed a clade (99% bt) with the morphological synapomorphy of a 2n  =  48 chromosome number. Hymenocallis henryae was sister to H. palmeri (82% bt) with several morphological synapomorphies including subcircular scapes, hyaline margins on their leaves, scape bracts that do not enclose the flowers in bud, and tepals that are colored green. Finally, H. puntagordensis and H. latifolia were sister taxa (84% bt) with the synapomorphy of persistent (versus deciduous) leaves and free filaments that are green distally. Rhizomes appear to have evolved twice within the southeastern United States species of Hymenocallis: once in the H. franklinensis H. choctawensis H. gholsonii H. pygmaea H. crassifolia H. duvalensis clade and once in the clade containing H. godfreyi, H. rotata and H. tridentata. The alliances determined by Traub for the southeastern United States species of Hymenocallis are generally supported based on this molecular and morphological analysis.

Eupatorium ×truncatum (Asteraceae) is distributed throughout the eastern United States and is thought to have originated from interspecific hybridization between E. perfoliatum and E. serotinum. This study confirms the hybrid origin of one E. ×truncatum population in central Indiana through analysis of DNA sequence data from nuclear ITS and corroborates the morphology-based hypothesis that E. perfoliatum and E. serotinum are its progenitors. Moreover, two single-copy nuclear loci showing fixed differences between the parents were in the heterozygous form in all hybrids analyzed, suggesting that these are all F₁ hybrids. Plastid psbA-trnH intergenic spacer sequences identify E. serotinum as the maternal progenitor of all sampled hybrids.

Three species of Platygramme in North America (north of Mexico) are treated, two of which are newly reported for the continent (P. pachnodes and P. praestans). The new combination Platygramme pachnodes is proposed for Phaeographina pachnodes (basionym Graphis pachnodes).

It is commonly believed that only a single species of Phragmites (Gramineae) occurs in North America. Here, field observation shows greater morphological differences than previously recognized between an introduced East Coast population and a native Gulf Coast population, and are sufficient to justify specific rank for each. These differences are discussed and illustrated, and a key is provided for separation. The introduced population, and the widespread northern native population (not studied), are treated as P. australis, and the Gulf Coast population as P. karka. Nomenclatural uncertainties are noted.