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Volume 88 — Issue 1 (May 2023)

A Morphometric Analysis of the Cyperus squarrosus-Cyperus granitophilus Complex in North America, with the Description of a New Variety of Cyperus squarrosus

March 31, 2023

Morphometric data were used to investigate the relationship between Cyperus squarrosus and related C. granitophilus, with particular attention to populations of C. granitophilus recently reported from granite outcrops in Texas and Oklahoma. Data for 23 characters (variables) taken from 406 voucher specimens were analyzed using principal component analysis (PCA), discriminate analysis (DA), multivariate analysis of variance (MANOVA), and a Euclidian distance dendrogram. Results (1) strongly support the treatment of C. granitophilus and C. squarrosus as separate species but (2) provide at best weak evidence for formal recognition of C. squarrosus var. runyonii and (3) indicate that the Texas and Oklahoma populations recently reported as C. granitophilus are more closely related to C. squarrosus than C. granitophilus.

Scientific Note: A Resurvey of Rhododendron eastmanii (Ericaceae) Populations in the Sumter National Forest, South Carolina

March 31, 2023

Rhododendron eastmanii is a species endemic to South Carolina and common in the Enoree Ranger District of the Sumter National Forest. A four-year study was undertaken to revisit known populations and to locate new populations. A total of 2,035 individuals in 38 populations were documented, including 663 seedlings, 705 non-flowering adults, and 667 flowering individuals. Plants were most commonly found on mature hardwood slopes above headwater streams. Pollinator visitors included eastern tiger swallowtail (Papilio glaucus), pipevine swallowtail (Battus philenor), and bumblebees (Bombus spp.). Concerns for the future of the species were noted due to deer browsing and subcanopy shading, especially from Acer leucoderme (a native tree) and Elaeagnus umbellata (an introduced shrub). This survey results in a better understanding of the species distribution and documents its demographic changes over time.

Life After Privet: Plant Community Dynamics in a Forested Wetland Following Removal of the Invasive Ligustrum sinense Lour

April 27, 2023

Chinese privet (Ligustrum sinense) invasion has been found to reduce native species richness and abundance of both herbaceous and woody plants and is a serious threat to wetlands in the southeastern United States. To determine the relationship between privet removal and understory vegetation, we performed surveys on a forested wetland from which L. sinense had been partially removed over a two-year period. Plant community composition, vegetation cover and species richness as well as soil moisture and PAR were recorded in removal and control (Privet-Present) plots in herb, shrub and tree layers. As expected, herb-layer removal plots were wetter and less shady, with more than four times higher cover of native and non-native species. Total species richness and native species richness were both higher in herb-layer removal plots, though non-native species richness did not differ. Shrub-layer removal plots were much less dense, with 1/100 the basal area of shrubs than control plots. Tree-layer plots did not differ in any measure, suggesting that control and removal plot types were historically similar and continued to support comparable overstory vegetation. The composition of woody seedlings in the herb layer did not reflect the mature overstory in either plot type, although several of the most abundant woody seedlings were those of dominant wetland species. We conclude that immediately following L. sinense removal, native species outperform non-natives, both in cover and species richness in the herb layer. The poor recruitment of woody seedlings and saplings as well as the rapid invasion of invasive Japanese stiltgrass (Microstegium vimineum) may thwart restoration efforts, however. To ensure the wetland reaches its pre-invasion community structure, it may be necessary to plant native tree saplings and nurture them through the shrub layer to maturity.

Noteworthy Collections: Maryland and Virginia

April 27, 2023

We have compiled data on 15 taxa (5 woody and 10 herbaceous) as established (9 taxa) or adventivewaif species (6 taxa) in Maryland (2 taxa) and Virginia (13 taxa) that are not considered definitive elements of each state’s extant flora. The woody taxa are Acer ginnala, Corylus avellana, Pyrus betulifolia, Tilia cordata, and Vaccinium virgatum. The herbs include Crocus tommasinianus, Daucus pusillus, Dracocephalum parviflorum, Euphorbia mercurialina, Indigofera hirsuta, Opuntia engelmanni var. lindheimeri, Pilea microphylla, Polycarpon tetraphyllum, Saxifraga stolonifera, and Silene flos–cuculi spp. flos-cuculi. We provide updated taxonomic information, range clarifications, supplemental habitat data, and other details about our voucher specimens and other collections.
Photo credit: John Klinovsky

Plant and Arthropod Community Responses to Fire in a Glade-Forest Landscape Matrix

May 30, 2023

Fragmented landscapes are a mosaic of ecosystems containing diverse communities of plants and herbivorous arthropods. Plant responses to fire in fire-prone ecosystems are well documented, but less is known about how plant-herbivorous arthropod interactions respond to fires. This study compared the responses of plant communities and their interactions with herbivorous arthropods to fire in a highly fragmented fire-prone glade system. Due to the mosaic landscape of the study site, three habitat types were chosen to delineate communities based on plant species composition, geology, and proximity to each other: small enclosed glade, large open glade, mixed hardwood forest, and pine savanna. From 2016–2019, we observed the interspecific interactions between plant and arthropod communities in the Ketona dolomitic glades of Bibb County in central Alabama. We identified plants to genus or species and recorded evidence of herbivory by seven herbivore guilds of arthropods. We used non-Metric Multidimensional Scaling and Analysis of Similarity to determine patterns of change between the habitats and across years for both plant species and interactions with herbivorous arthropods. Plant communities return to pre-burn species diversity within two years. Plant community composition was grouped strongly by habitat type and year, while interactions with herbivorous arthropods were homogenous across habitats but grouped strongly by year. Tracking herbivorous arthropod guilds using plant association evidence is useful for rapidly and temporally determining overall responses in herbivorous arthropod guild composition. However, it is too coarse to determine changes and responses in herbivorous arthropod guild composition at finer spatial scales.