Taxonomic recognition of Solidago lancifolia (Torrey & A. Gray) Chapman and diagnostic characters used for identification have vacillated among floras and treatments. Fieldwork greatly expanded the specimen base in US herbaria, extended the known range in Tennessee, and identified new occurrences in North Carolina and Virginia. A morphometric analysis of herbarium specimens identified qualitative and quantitative characters unambiguously diagnostic for S. lancifolia. These included the presence of glands on the phyllaries; long, wide-diameter rhizomes; thick stems; and a long pappus on disk florets. Using these characters, an analysis of herbarium specimens corrected widespread misidentifications and showed that S. lancifolia is strictly endemic to a 12-county region encompassing the high elevations (> 1,400 m) in the mountains of southwestern Virginia, northwestern North Carolina, and northeastern Tennessee. Based on the narrow geographic range and small population sizes, prior uncertainty of the taxonomic validity and geographic range of S. lancifolia has been resolved. Consequently, for North Carolina and Virginia, the recommendation is for an upgrade in the conservation status to “Endangered” with a state rank of “S1.” Moreover, the narrow geographic range and small number of populations are consistent with a global rank of “G2” and consideration as a federal Species of Concern.

Lily leaf spot, a fungal foliar disease caused by Pseudocercosporella inconspicua, leads to premature senescence of aboveground tissues in Lilium grayi. At Roan Mountain, North Carolina/Tennessee, the disease was most prevalent and most severe in seedlings and juveniles. In the two growing seasons assessed, 59 and 70% of mature plants experienced disease-induced premature senescence. Plants with disease lesions on seed capsules matured fewer capsules and had fewer seeds per capsule, and seeds had reduced viability. Disease prevalence over the growing season followed a sigmoidal pattern typical of polycyclic epidemics. Plants with low and high disease severity occurred in clusters whose locations were stable across growing seasons. Prior to the recent description of lily leaf spot, L. grayi was already considered threatened or endangered in each of the three states where it naturally occurs. Therefore, this infectious disease poses conservation and management difficulties because increases in plant density can be expected to lead to enhanced disease transmission. Lily leaf spot of L. grayi is best characterized as an annually recurring epidemic because of high prevalence rates, strong impacts on all life stages, and reductions in seed production and viability.

Coastal Everglades are experiencing a steady increase in soil and groundwater salinity due to sea level rise. Increase in soil salinity threatens plant assemblages in coastal upland forests of Everglades National Park (ENP). Here we test the effects of increase in soil salinity on saplings of tropical woody species common to the coastal hammocks (forests) of ENP, FL. Saplings were subject to salinity levels ranging from control (freshwater) to 30 parts per thousand (ppt). Significant mortality was observed among species of hardwood hammocks such as Piscidia piscipula (L.) Sarg., which displayed 7%, 20%, and 30% mortality in salinity levels of 5, 15, and 30 ppt, respectively. The canopy-forming Conocarpus erectus L. (buttonwood) and Cynophalla flexuosa (L.) J.Presl, an understory shrub of buttonwood hammocks, exhibited 100% survival across salinity treatments. Stomatal conductance and final shoot biomass were significantly higher in control than 30 ppt for all species except C. flexuosa. Our results suggest that the species of coastal hardwood hammocks show greater vulnerability to increase in soil salinity than the species of buttonwood hammocks. Increase in soil salinity will lead to decline in species diversity, biomass, and canopy height of coastal upland communities.

Invasive plants often benefit from ecological disturbances that allow them to gain a foothold and to achieve competitive superiority. One form of anthropogenic disturbance in coastal ecosystems is the deposition of sediments dredged for navigation and other purposes. Examples can be found in New York's Hudson River Estuary, now colonized by many terrestrial and aquatic invasive plant species, whose success may be related in part to a variety of anthropogenic disturbances. We investigated spatial patterns of a widespread colonization by Celastrus orbiculatus Thunb., Oriental (or Asiatic) bittersweet, across the 425-ha Schodack Island State Park, Rensselaer and Columbia Counties, NY. Populations were mapped and surveyed on a fixed grid to determine general distribution patterns. Of 146 sites examined, 59% contained populations of the target species, with mean estimated liana age of 9.3 yr, indicating a relatively recent population expansion. Stem densities were 88% higher in sites with dredged material substrate, which was found to be coarser, lower in organic matter, and lower in major nutrients. High-density populations of C. orbiculatus (> 50% cane cover) were found only on sites with dredge spoil substrate. Experimental tests were performed at 25 locations (five different site types) based on substrate properties (dredged substrate or native forested floodplain) and local C. orbiculatus densities (absent, < 10%, or > 50%). Ten greenhouse-grown seedlings and 100 wild-harvested seeds were planted at each site and then tracked for their survival, growth, and evidence of arbuscular mycorrhizal (AM) inoculation. Transplants survived and grew at similar rates among the site types, but mean field germination, although low overall (< 5%), was three times higher in the dredge spoil substrate. All recovered transplants were inoculated in the field by AM, with somewhat higher within-plant frequencies (99.0% vs. 80.0%) among fine root sections from dredge spoil substrate. No overall differences in inoculation were found among sites with different C. orbiculatus densities, suggesting generalist fungal mutualisms. Most sites with dredge spoil deposition lie above tidal flood zones and thus are out of contact with natural disturbance dynamics, which may help explain the observed differences between substrate types. Given the widespread distribution and high dispersal potential of this plant species, targeted management will be needed to protect ecologically sensitive areas of the park, and our work suggests that management should include efforts to restore and enhance contact with natural tidal dynamics.

Plants store nonstructural carbohydrates (NSCs), such as sugars and starch, to use as carbon and energy sources for daily maintenance and growth needs as well as during times of stress. Allocation of NSCs to storage provides an important physiological strategy associated with future growth and survival, and thus understanding the seasonal patterns of NSC reserves provides insight into how species with different traits (e.g., growth form, leaf habit, wood anatomy) may respond to stress. We characterized the seasonal patterns of NSCs in four woody boreal plant species in Minnesota, USA. Sugar and starch concentrations were measured across the year in the roots and branches of two conifer trees, black spruce (Picea mariana (Mill.) B.S.P.) and eastern tamarack (Larix laricina (Du Roi) K. Koch), as well as in the leaves and branches of two evergreen broadleaf shrubs, bog Labrador tea (Rhododendron groenlandicum (Oeder) Kron & Judd) and leatherleaf (Chamaedaphne calyculata (L.) Moench). In general, seasonal variation was dominated by changes in starch across all organs and species. While similar seasonal patterns of NSCs were observed in the shrubs, different seasonal patterns were observed between the trees, particularly in the roots. Our results suggest that species-specific traits likely have consequences for organ-level storage dynamics, which may influence whole-plant growth and survival under global change.

Many studies have examined variation in nuclear DNA content across environmental gradients. However, these studies have often produced conflicting results. We speculated that the conflicting phenomenon resulted from insufficient sampling of the taxa and limitations in the geographical range. To clarify whether the relationships between nuclear DNA content and environmental gradients are universally nonlinear across a wide geographical range, we chose 3,290 herbaceous angiosperm species, which have both nuclear DNA values in the Angiosperm DNA C-values database and geographical distribution information in the Global Biodiversity Information Facility (GBIF) database. Then we selected 10 global longitudinal transects each with a span of 15°, and evenly divided each transect (from 82.5°N to 82.5°S) into 22 blocks. We obtained geographical records (presence or absence) of these 3,290 species together with 14 bioclimatic factors within these blocks, and calculated the average DNA 1C-values and genome sizes of the species in each block. By using polynomial functions, we analyzed the correlation of nuclear DNA values with latitude. By using the Gaussian model, we further analyzed the correlation of nuclear DNA values with the 14 bioclimatic factors. Finally, we also performed quantile regression analyses to elucidate the differences in geographical distribution pattern among groups with nuclear DNA values of different sizes. We found that species in equatorial areas had the smallest mean nuclear DNA values, the values increased with latitude for both the northern and southern hemispheres following nonlinear functions. We found that nuclear DNA contents decreased with increasing latitude in the Arctic. The change of nuclear DNA content with latitude was weaker in the species groups with smaller nuclear DNA content than those with a larger nuclear DNA content. Nonlinear relationships (following Gaussian models) also existed between nuclear DNA values and the 14 bioclimatic factors, such as annual precipitation and mean temperature. Therefore, the relationships of nuclear DNA content with either latitude or the 14 bioclimatic factors covarying with latitude are universally nonlinear across a global geographical gradient. Nuclear DNA contents are of ecological significance for angiosperms. There exist obvious differences in the geographical distribution patterns among species groups with nuclear DNA values of different sizes, with a selective advantage for species with small nuclear DNA content in extreme environments.

Campylocentrum includes over 70 species distributed throughout tropical America. In this paper a synopsis of this genus in Colombia is presented. The occurrence of 16 species of Campylocentrum in this country was confirmed. Morphological characteristics of all the species are presented and illustrated by line drawings of their perianth segments. A key to the identification of the species in this genus reported in Colombia and adjacent areas is provided along with information on their ecology, habitat, and geographical ranges. A new species of Campylocentrum discovered during this study is described and the status of unconfirmed taxa briefly discussed.

As a result of our taxonomic study of the genus Erythrina L. (Leguminosae, Papilionoideae, Phaseoleae) in Brazil, 12 lectotypifications, 2 being second step, 1 accompanied by an epitype, and 3 new synonyms, are proposed. Erythrina mulungu, previously considered a synonym, is presented as the correct name for a species formerly known as E. dominguezii, and E. martii is considered a synonym of E. falcata, a conserved name.