Identifying the areas most vulnerable to a species' invasion within a habitat or region is crucial to managing and minimizing that species' eventual effect. The exotic annual grass Microstegium vimineum often occurs in the greatest density along disturbed corridors, such as waterways and trails, within otherwise undisturbed forests. We tested the hypothesis that such linear features within forests are correlated with invasion patterns. We surveyed linear transects along intermittent streams and foot trails through eight upland forests of different ages, as well as control transects within each forest that were distant from any type of linear feature. We documented significantly larger and denser patches of M. vimineum along transects in young forests than those in old stands. Streams and trails were similarly more invaded than control transects, and M. vimineum was distributed much more patchily away from such corridors. Isolated individual patches of M. vimineum (along neither streams nor trails) demonstrated the potential to expand at approximately 1 m over 1 y, although 11% of plants appeared farther than 2 m from their parent patch. Although germinants appeared downslope of the parent patch two to four times more frequently than upslope, the mean distance of spread was equivalent in both directions. Control efforts should focus on excluding the species from corridors that could allow entry, particularly in older forests.

Sibbaldia procumbens occurs in arctic and alpine environments in widely disjunct locations in North America, Europe, and Asia. It is one of the rarest native plants in New England, with only a single station in New Hampshire. To inform conservation efforts for this species near the southeastern periphery of its North American range, we studied S. procumbens in alpine snowbeds on the Uapishka Plateau (Monts Groulx) in central Québec, a relatively poorly known mountain range in the Grenville geologic province where the species is abundant enough to evaluate associated site characteristics. Sibbaldia procumbens was positively correlated with slope, southern aspect, and elevation, with the highest abundances associated with 22–26° slopes, 100–230° aspect, and elevations of 1024–1039 m. At our site in Québec, S. procumbens was more abundant in association with bare rock, supporting the findings of previous authors that S. procumbens may benefit from some level of disturbance. We also quantified the dominant vascular plant species in both snowbed and summit communities on the Uapishka Plateau.

The new Peruvian Draba cajamarcensis and Chinese D. jiulongensis are described and illustrated. They are most similar to D. hallii (Colombia, Ecuador) and D. bartholomewii (China: Qinghai, Sichuan, Tibet), respectively. The distinguishing characters between members of each species pair are presented.

Kosteletzkya C. Presl includes 17 species that are about evenly distributed between Africa and the northern Neotropics. The seven species with known chromosome numbers are exclusively diploid (n  =  19). Here, 47 new chromosome counts are reported and the nomenclature of five of the earlier-counted species is updated. The counts confirm chromosome numbers for six species and provide first counts for eight species. Four of the latter, all African, are tetraploids, and another African species is a hexaploid. Amphi-Atlantic distributions and polyploidy in other malvoid groups are considered. Polyploidy evidence suggests an African origin for the genus.

Chattahoochee River National Recreation Area is administered by the National Park Service, US Department of the Interior, and comprises 2618 ha (6470 acres) in 15 land units along 77.3 km (48 mi) of the river corridor in Georgia, from the Buford Dam on Lake Lanier (near Sugar Hill) south to Peachtree Creek in Atlanta. A floristic survey was conducted to provide Park Service personnel with a vouchered plant species checklist, supplemented with salient information such as relative abundance, locality data, and general community type. Twelve collecting trips conducted in 2006–2007 yielded 570 species and three varieties of vascular plants, including 169 species not previously vouchered for the park. Identifications of specimens in the park herbarium from prior surveys were also verified and incorporated into the annotated list, resulting in a total of 827 plant species vouchered for the park flora. The five largest families were Asteraceae (108 spp.), Poaceae (66 spp.), Fabaceae (51 spp.), Cyperaceae (44 spp.), and Rosaceae (30 spp.). According to state rankings, 13 rare plant species occurred within the study area and 19% of the noncultivated flora was exotic. Clinopodium gracile, native to Asia, was verified from Georgia for the first time. A vouchered checklist of vascular plants and descriptions of the general plant communities are included, as well as a list of unvouchered species previously reported from the park.