A new status for Lycopus laurentianus is proposed: Lycopus americanus subsp. laurentianus, and the taxon is newly reported from the United States with occurrences in Maine, New Hampshire, New York, and Vermont. Six occurrences in Vermont and three in New York were discovered on the shores of Lake Champlain in 2007. Subsequent review of L. americanus specimens from herbaria yielded more occurrences of L. americanus subsp. laurentianus in New York and Vermont, as well as new occurrences in New Hampshire and in Maine. Important publications and data previously available only in French of this relatively obscure taxon are also presented. Nutlet morphology is presently the only reliable diagnostic character separating L. americanus subsp. laurentianus from L. americanus subsp. americanus.

Natural areas are intended to preserve biodiversity and understanding how well they fulfill this role is crucial as pressure from anthropogenic disturbances like habitat loss increases. We re-inventoried the flora of Baker Woodlot in East Lansing, Michigan, 40 years after an initial study to document changes in community composition. Both inventories were based on vascular plant collections vouchered by specimens and deposited in the Michigan State University Herbarium. We compared results with 10 similar floristic change studies in northeastern North America to understand patterns in species turnover, accounting for gains and losses of natives and nonnatives. In Baker Woodlot and across the comparable studies, total richness stability masked a consistent pattern of native losses and nonnative gains. In Baker Woodlot, total richness increased marginally (3%; 11 species), reflecting a net loss of 19 natives and a gain of 30 nonnatives. Across the comparable studies, richness increased by 3.6%, but seven native species were lost per decade on average. Nonnative turnover was higher compared to native turnover and positively correlated with time between inventories. Despite net loss of natives, Baker Woodlot experienced only a slight decline in floristic quality. Baker Woodlot remains a high-quality beech-maple forest, which is a prominent component of Michigan's biodiversity. Species richness alone does not adequately address biodiversity concerns. In Baker Woodlot and comparable forests, natives are being replaced by nonnatives.

Molecular analyses and cytological data have shown that Silene multinervia, which has always been placed in section Conoimorpha and often regarded as a heterotypic synonym of S. coniflora, is a separate taxon in a distinct clade. A comparison between S. multinervia and the members of section Conoimorpha is provided, showing that the species can be distinguished by both vegetative (plant height) and reproductive (flower number per inflorescence, calyx vein number, calyx length, petal apex shape, fruit length, carpophore length, and seed diameter) characters. Cytological, molecular, and morphological evidence support recognition of S. multinervia as a member of a new section endemic to southwestern California and northwestern Mexico (Baja California). Therefore, Silene sect. Californicae, sect. nov. (type: S. multinervia) is here proposed.

Dichanthelium scoparium (Poaceae) is a robust, rhizomatous panic-grass of the eastern United States. Most common in the southeast, it is considered rare in New York and had not been observed in New England since 1931. In recent years, we have discovered four new populations in Massachusetts and Rhode Island, reestablishing the species as extant in New England. To establish context for these discoveries, we evaluated past records from New England and New York, principally by inspecting digital images of voucher specimens, relying on the readily discernible diagnostic characters of the species. Using the subset of 22 verified records, we elucidate the regional distribution of the species and discuss patterns of habitat and ecological processes that may affect its presence and persistence on the landscape.