Recently, the native shrub or small tree Aralia spinosa has been reported from the northeastern United States farther north of its traditional range, while the Asian shrub A. elata has been reported to be naturalizing across the same region. Herbarium and field studies have clarified the current ranges of A. spinosa and A. elata in the eastern United States, with almost all recent reports of A. spinosa in the northeastern United States north of Maryland and Delaware being based on misidentifications of A. elata. Aralia elata is well established and rapidly spreading throughout all 25 counties in the New York metropolitan area. The most reliable characters for separating the two species are the length of the central inflorescence axis, fruit size, and seed size. Many herbarium specimens of these woody Aralia species cannot be confidently identified to species because they lack or have incomplete inflorescences/infructescences. Proper preparation of voucher specimens requires at a minimum the collection of the proximal portion of the inflorescence/infructescence.

Calamagrostis perplexa is a New York State endemic grass species, hypothesized to be of hybrid origin, that previously was known only from a single locality. We provide a summary of its taxonomic history, report new New York records and ecological information for the taxon, and include a principal components analysis and key characterizing morphological variation in C. perplexa and its putative close relatives C. canadensis, C. porteri, C. rubescens, and C. scribneri. Calamagrostis perplexa is now known from two extant populations and a third population of unknown status; it remains a New York state endemic.

A survey of oligohaline and mesohaline tidal marshes along the upper reaches of eight tidal rivers in the Great Bay Estuary of New Hampshire was conducted to document the occurrence of eastern grasswort, Lilaeopsis chinensis, a state-listed, rare species. Historical sites were visited to assess the presence, absence, or significant population changes of this rare coastal species. We re-located four of five historically documented element occurrences, noted the plant's potential expansion on several rivers and a decline at three other sites, and identified a new occurrence on a river system with no prior documented accounts. The results suggest that overall, L. chinensis has been relatively stable for the last 60 years, although the loss of plants at three of the sites suggests it is threatened by continued development (dams and tidal restrictions) and associated impacts to water quality.

Alvars in the vicinity of Enterprise, Northwest Territories, had 87 species of vascular plants. Of these, 14 were frequent or at least locally abundant, including: Juniperus horizontalis, J. communis var. depressa, Geum triflorum var. triflorum, Carex richardsonii, Populus tremuloides, Elymus trachycaulus subsp. trachycaulus, Koeleria macrantha, Saxifraga tricuspidata, Artemesia campestris subsp. borealis, Senecio lugens, Arctostaphylos uva-ursi, and Galium boreale. Of the trees comprising the surrounding forest, only Populus tremuloides and Pinus banksiana were common in the open areas. The cliff tops had fewer species but they also had some species of arctic and high boreal affinity that were absent from the alvars. Associations characterized by Deschampsia caespitosa occurred in lower areas of alvar that collect run-off, whereas higher areas were characterized by a variety of plants including Carex richardsonii, Elymus trachycaulus, and Geum triflorum. Cracks in the limestone pavement in elevated areas were occupied by Pinus banksiana and Juniperus communis. Approximately 12% of the species present were rare and/or restricted, including Avenula hookeri, Carex filifolia, and Dodecatheon pulchellum. Compared to the alvars of the Great Lakes region, the alvars and cliff tops of Northwest Territories had a much higher percentage of species that were also found in the Beringian region of northwestern North America. Higher numbers of boreal, arctic, and cordilleran species also contributed to the distinctive nature of Northwest Territories alvars, based on clustering of similarity coefficients from species presence or absence data. The alvar flora of Northwest Territories is believed to have been established in the region of Great Slave Lake between 10,000 and 8000 years ago, prior to invasion of the boreal forest. At this time, the northwestern Beringian and Cordilleran floras met the retreating tundra and prairie floras from the south in an expanding ice-free corridor. The relict flora of Northwest Territories alvars and cliff tops includes species of the Beringian steppes and tundras such as Plantago canescens, species of the central North American plains such as Geum triflorum, and many species that could have originated from the prairie-like habitats of either region. This unusual relict flora, originating in early postglacial times, is now isolated within the present boreal forest that spread through the region approximately 8000 years ago.

A taxonomic survey is presented for Leucophysalis. The genus is of interest because L. grandiflora has the northernmost distribution of any Solanaceae in North America and because of its possible link to certain Asian species of the family. A key to species, synonymy, and a discussion of generic relationships is included.

Field and herbarium research has revealed three newly recognized introduced and naturalized mosses in the northeastern United States. Rhytidiadelphus squarrosus, as that name is often applied in eastern North America, consists of a widespread common native species, R. subpinnatus, a carpet-forming moss of wet conifer and conifer-hardwood forest, and R. squarrosus in the strict sense, an introduced and naturalized moss that appears to be infrequent in eastern North America and restricted to weedy habitats such as lawns. Kindbergia praelonga is documented to occur on Nantucket Island, Massachusetts, in lawns in Nantucket town, indicating that it is a naturalized member of the bryoflora. There may also be native populations of this moss elsewhere in eastern North America, but this is unconfirmed. A moss of the southeastern and midwestern United States, Funaria flavicans, has been found with mature sporophytes in flower pots at a retail nursery on Nantucket Island in circumstances indicating it is an adventive. It may be a waif, or possibly a member of the naturalized bryoflora of Massachusetts, if in the future populations outside cultivation are found. New occurrences of a European moss, Psuedoscleropodium purum, from Maine, New Hampshire, Massachusetts, and in other places in eastern North America (Nova Scotia and North Carolina) add substantially to the previously known distribution of this moss. These new collections were in part from residential lawns and similar habitats outside of cemeteries where most of the previously known occurrences were concentrated, which may indicate that this moss is spreading.

A qualitative floristic survey of Wallace Woods, Linesville, Pennsylvania, was conducted during the growing seasons of 2005–2007. The 12.9 ha tract is situated in the western portion of Crawford County, within the Northwestern Glaciated Plateau Section of the Appalachian Plateaus Province. Wallace Woods has been the property of the Pymatuning Laboratory of Ecology through the University of Pittsburgh since 1962. Seven habitats were delineated within this site: 1) Upland Hemlock–Hardwoods Forest, 2) Elevated Alluvial Woodland Terrace, 3) Golden Saxifrage Woodland Seep, 4) Skunk Cabbage Swamp, 5) Alluvial Creek Floodplain, 6) Riparian Creekbank, Gravelbars, and Mudflats, and 7) Culturally Derived Ruderal Roadside. The vascular flora consisted of 384 specific and infraspecific taxa in 229 genera from 83 families. Eighty (20.8%) taxa were exotics. Plant division representation was one Equisetophyta, three Lycopodiophyta, 15 Polypodiophyta, two Pinophyta, and 363 Magnoliophyta (97 Liliopsida, 266 Magnoliopsida). The largest five families were the Asteraceae (40), Poaceae (37), Cyperaceae (32), Rosaceae (23), and Fabaceae (12). Twenty-one taxa (5.5%) were new records for Crawford County.