Flowering phenology, or the timing of plant reproduction, is a key component of plant fitness, influencing plant survival, reproduction, and the presence (or absence) of temporal reproductive barriers between closely related species. Flowering phenology often varies across space, and advancing spring phenology is a common response to anthropogenic climate change. Characterizing phenological variation at higher taxonomic levels can reveal whether related species vary in their sensitivity to climate change. We characterized flowering phenology across space and through time in the dimorphic cleistogamous genus Triodanis using vetted digital herbarium and iNaturalist records of Triodanis species spanning 153 years across the contiguous United States. We found considerable overlap in peak flowering time in all seven Triodanis species, suggesting that factors other than flowering time, such as self-fertilization, may contribute to the maintenance of species barriers in this genus. Geography influenced the peak-flowering date in four species, but the direction and strength of these relationships varied between species, perhaps reflecting local variation in abiotic conditions and species-level differences in flowering cues. We found phenological advancement over the past century in four of seven Triodanis species, suggesting that this genus is potentially tracking climate change through flowering time shifts.

Grassy openings are relatively uncommon on the unglaciated Allegheny Plateau, and the limited sites that do exist contribute disproportionately to the diversity and biological heritage of the region by providing habitat for locally uncommon plant species. Three grassy openings with areas of 0.1–0.2 ha are present on limestone-capped ridgetops at Strouds Run State Park in Athens County, Ohio. Although previous inventories of the park have documented the presence and character of these openings, the sites had not been thoroughly surveyed. Here we describe the vascular flora and soils of the openings and recommend management activities to conserve grassy openings within the park. The openings were surveyed monthly during the 2013 growing season, with frequent additional visits during the growing seasons in 2014–2019. Soils were collected from the openings and adjacent forest for analysis of pH, texture, and bulk density. We documented 135 species of vascular plants across the three sites; 27 were nonnative. The openings were dominated by forbs and grasses intermixed with woody species characteristic of limestone glades (e.g., Celtis pumila and Juniperus virginiana) and other open habitats. Andropogon gerardi was the dominant grass and openland forbs such as Asclepias tuberosa, Lithospermum canescens, and Ratibida pinnata also occurred in the three openings. Soil pH was significantly higher in openings and edge zones than in the forest matrix, suggesting that soils are a contributing factor shaping the grassy communities. However, woody plant encroachment was progressing inward from the edges of the openings, suggesting that a lack of disturbance is threatening the persistence of these unique communities. We suggest selective thinning of woody species to maintain the character and diversity of these sites; the practicality of controlled burns in small sites at close proximity to residential structures is limited.

Desmids (sensu lato) are a group of morphologically diverse, freshwater algae, which have been used as biological indicators in some regions. In this study, we sampled three New England ponds from 2017 to 2019 and recorded their desmid floras. We then curated early- to mid-20th-century floristic data from the same ponds and compared them to our findings from 2017 to 2019 to document changes in desmid assemblages over the last 100 years. We assessed the past and current conservation value of the ponds using desmids as biological indicators. We documented a major decline in desmid diversity and conservation value of two of the ponds, but we documented remarkable diversity in Hawley Bog in western Massachusetts, with 66 taxa newly reported from the locality. Additionally, we documented the first record of Micrasterias brachyptera from New England. To aid future floristic efforts, we provided our species records and images in a public repository, the community-science database iNaturalist.