Vegetation patterns in the coastal salt pond marsh system at Odiorne Point State Park in Rye, New Hampshire, the state's only viable example, are described based on recent surveys and historical data. Four natural communities occur within the system: coastal salt pond flat, coastal salt pond emergent marsh, coastal salt pond meadow marsh, and highbush blueberry–winterberry shrub thicket. The first three communities are newly described in New Hampshire and the northeastern US coastline. A total of 69 native or naturalized vascular plant taxa from 54 genera and 33 families have been documented in the system at Odiorne Point between 1967 and 2011. The families best represented were Cyperaceae (10 taxa), Poaceae (9 taxa), and Asteraceae (6 taxa); the largest genera were Eleocharis (4 taxa), Hypericum (4 taxa), and Agrostis (3 taxa). In 2011, only 35 of the 69 plant taxa were documented; a difference that can be attributed, at least partially, to the variable nature of hydrologic and salinity influences on the system. Of the 69 plant taxa, three are rare in New Hampshire and five are both non-native and invasive in the state and region. The uncertainty of the nativity status of Typha angustifolia, the dominant species in the marsh, has significant implications for future management decisions. Measurement of surface and pore water salinity in late summer of 2011 revealed essentially fresh water conditions at the surface (1.1 ± 0.5 ppt SE), whereas pore water occurring 10 cm and 40 cm below the soil surface was mesohaline (5.8 ± 1.8 and 8.1 ± 1.8 ppt SE, respectively). Mean pore water salinity differed significantly among the natural communities examined, suggesting that hydrology and salinity influence species composition and distribution within coastal salt pond marsh systems. This globally rare system, distributed from Maine to New Jersey, shares similar dominant species across its range, although some of the state rare species it supports differ along a latitudinal gradient.

The invasive Asiatic red alga Gracilaria vermiculophylla has recently spread rapidly around the globe. In the Northwest Atlantic, it was first collected in Virginia during 1998; in New England, it was first recorded from Narragansett Bay, Rhode Island in 2007. Until now, the specific dates of its introduction and current distribution in New England have been poorly understood. We employed a combination of field collections, evaluations of historical herbarium specimens, and molecular investigations (including mt-CO1 gene sequencing) to document its present distribution and approximate dates of introduction within New England. We found G. vermiculophylla at 18 of 24 Northwest Atlantic sites growing with native Gracilaria populations. Presently, it is recorded from Stamford, CT to Greenland, NH, with no populations known from five Maine sites where the native G. tikvahiae grows. Molecular screening of historical specimens revealed that G. vermiculophylla was collected from five sites in Massachusetts during 2000, whereas it was first documented in New Hampshire from the middle of the Great Bay Estuarine System (i.e., Dover Point) during 2003. In Rhode Island, initial specimens were documented during 2007, and those in Connecticut were first confirmed during 2010. As G. vermiculophylla has gone primarily undetected in New England since at least 2000, this highlights the difficulty of documenting the arrival and spread of an invasive species that closely resembles a native congener. Hence, DNA sequencing is critical in clarifying the introduction and expansion of such non-native seaweeds.

The adaptive value of cleistogamous (closed and obligately selfing) flowers has been explored in theoretical and empirical studies, yet the effects of cleistogamy on reproductive isolation between diverging taxa has previously received little consideration. Two subspecies of the annual plant Triodanis perfoliata have diverged in their relative allocation to cleistogamous (CL) versus open or chasmogamous (CH) flowers. The subspecies have widely overlapping geographic distributions and produce viable hybrid offspring. Here, we use morphological diagnostic traits of T. perfoliata subsp. biflora and subsp. perfoliata to characterize their spatial distribution and test for evidence of hybridization at a site in Pitt County, NC. Sampling along a transect in the zone of contact revealed the presence of two distinct morphological types that were spatially mixed. In a separate study, offspring of CL and CH flowers from both subspecies were raised in a growth room, and diagnostic morphological traits were confirmed to differ significantly between the subspecies. In subsp. biflora, we found a significant difference between offspring of CH and CL flowers for both diagnostic traits analyzed, providing evidence for hybridization; for each trait tested, the mean for CH offspring in subsp. biflora deviated in the direction of the mean for subsp. perfoliata. In contrast, in subsp. perfoliata, we found no significant differences in morphological traits between offspring of CH and CL flowers. We suggest that differences in the number of CH flowers produced by each subspecies might explain the observed asymmetry in hybridization.

We conducted a vascular plant inventory of six National Park Service units in southwestern and south-central Alaska to establish baseline floristic information and identify species of conservation concern. Between 1998 and 2005, we collected 815 taxa, the majority of which were new records for one or more park units. We present descriptions of the rare taxa (Alaska Natural Heritage Program S1–S3 ranks) collected as part of the National Park Service inventories, as well as new collections that represent significant range extensions. Of the 45 taxa reported here, all but one are considered globally rare or rare within Alaska. Collections of six taxa, including the common species, represent range extensions of greater than 450 km, and collections of an additional 16 taxa were minor range extensions (> 150 km, < 450 km). We include brief synopses of the vouchers, including general notes on the biogeography and rarity of these taxa. These and previous collections support the demarcation of southwestern Alaska as an important zone of floristic convergence. The central Alaska Range also represents a unique assemblage of boreal and maritime-associated taxa.

In the division of Centaurium s. lat. into segregate genera in phylogenetic studies by Mansion and Struwe, the more recently described species C. blumbergianum is referable to Gyrandra. The new combination G. blumbergiana is published. A nomenclatural study of North American Lomatogonium indicates that the name L. rotatum was validly published by Fries, and that the only name based on specimens of the taxon native to the interior of western North America is Pleurogyne fontana. In order that this taxon may continue to be treated as an infraspecific taxon within L. rotatum, the new combination L. rotatum var. fontana is published.