Alvar landscapes occur in the glaciated region of New York where horizontally bedded limestones are covered by little or no soil. Major sites are found along the eastern end of Lake Ontario northwest of Watertown and underlain by the Black River Group limestones. They are naturally open landscapes with scant tree cover often restricted to bedrock crevices. New York alvars are home to state-rare elements, including seven natural plant communities and 57 rare plant species. Floristic assemblages are diverse and include several disjunct species with northern, southern and midwestern (prairie) affinities. The mosaic of distinctive plant communities is adapted to extreme environmental conditions including seasonal fluctuation in moisture and temperature, variable shallow soil depths, localized runoff patterns, and cryopedogenic processes. They are also subject to recurring human disturbances such as fuelwood and fence post cutting, accidental fires, and introduction of drought tolerant nonnative species. Combined, these factors support a surprisingly high biodiversity in alvar landscapes.

Najas muenscheri is an aquatic plant with a controversial taxonomy and poorly known geographic distribution, habitat, and conservation status. Authors have treated N. muenscheri as a species, as a variety and subspecies of N. guadalupensis, and as conspecific with N. canadensis. Some authors have reported it from four states (New Jersey, New York, Virginia, and Wisconsin), but most have reported it from only New York. Some have reported it exclusively from tidal habitats, whereas others reported it from both tidal and nontidal habitats. Largely because of these uncertainties surrounding N. muenscheri, its conservation status remains an open question. We utilized field work, herbarium research, and morphometric analyses of seeds to address these questions and test the hypothesis that N. muenscheri is a species distinct from N. canadensis. Morphometric analyses revealed statistically significant differences in seed length, seed width, and seed length/width for N. muenscheri and N. canadensis. Additionally, seeds of the two differ in surface texture, luster, and raphe prominence: alveolate and dull with a prominent raphe in N. muenscheri vs. smooth, shiny, and with an inconspicuous raphe in N. canadensis. These morphologic differences as well as their maintenance during multiple instances of syntopy indicate N. muenscheri and N. canadensis are distinct species. The complete known geographic distribution of N. muenscheri is in Maryland, New Jersey, and New York. Extant populations are known from only intertidal habitats in the Hudson River Estuary. Najas muenscheri appears to warrant the IUCN rank of Endangered, because of restricted geographic range, few populations (22 currently known), small population sizes, documented declines, and several serious threats to its survival.

In New York's Great Lakes coastal wetlands, particularly in barrier-protected and riverine systems along Lake Ontario, floating mats of emergent vegetation are common. The Braddock Bay Wildlife Management Area (WMA) includes four of these wetlands—Braddock Bay, Cranberry Pond, Long Pond, and Buck Pond—that have been affected by the hybrid cattail (Typha × glauca). Restoration efforts have focused on increasing habitat heterogeneity and reducing erosion, particularly through a barrier beach reconstruction in Braddock Bay and cattail mat excavation at all four wetlands. Our objectives were to (a) document changes in floating mats within Braddock Bay WMA using aerial and satellite imagery and (b) characterize mat vegetation and distance from the mat surface to mineral substrate (depth to mineral substrate) through recent monitoring surveys. We reviewed aerial and satellite imagery from 1930 to 2023 and quadrat vegetation survey data from 2018 to 2022 in Braddock Bay and Cranberry Pond. We also analyzed depth to mineral substrate in response to lake-level fluctuations. Floating mats persist in all four Braddock Bay WMA wetlands but show variations in vegetation composition and extent. Braddock Bay is primarily dominated by Typha × glauca, whereas Cranberry Pond contains fen communities with rare and state-threatened species. Median depth to mineral substrate steadily decreased across the wetlands since 2020 as Lake Ontario water levels declined from 2019. Our findings highlight the resilience and ecological importance of floating mats in coastal wetlands but also underscore the threats posed by invasive species, altered hydrology, and human disturbance. This study contributes a baseline understanding of floating mat dynamics, which will inform ongoing management, monitoring, and modeling efforts within the Great Lakes.

Algal blooms are characterized by a rapid increase in abundance of a singular algal species and can have important consequences for human health. The increase of global temperatures, precipitation events, and eutrophication have only further exacerbated the frequencies of bloom events observed worldwide. Euglena blooms are commonly reported in southeast Asian aquaculture operations and not in northern latitude urban rivers. Identifying and understanding the conditions associated with this bloom in Ellicott Creek (New York, USA) is paramount given the frequency of human and domestic animal interactions within this water. We conducted regular collection of in situ conditions and whole water analysis during the summer of 2021. We assessed algal biomass, assemblage composition, and Euglena viridis cell density. Generally, increased rainfall resulted in excessive loads of phosphate that drove bloom formation. Other nutrients did not contribute significantly. This study provides key insights into the role that precipitation and excess nutrients can play in E. viridis blooms, which are increasing in number in this region. The information provided here can form the basis for future actions to mitigate these blooms.

Since the last published checklist of vascular plants of New York State in 2017, the flora of the state as well as the understanding of that flora has changed. Ongoing research has revealed species that were not previously accounted for, new erroneous reports, and new details on previously accepted species. Presented here is this information for the native portion of the flora. Nonnative species will be dealt with in a subsequent publication. An additional 25 New York native vascular plant taxa are now considered part of the flora of the state. These are Carex adusta, C. arcta × C. brunnescens, C. cryptolepis × C. flava, C. hystericina × C. schweinitzii, C. tenuiflora × C. trisperma = C. ×trichina, Cyperus grayi × C. lupulinus, Cypripedium candidum × C. parviflorum var. makasin = C. ×andrewsii nothovar. andrewsii, Elymus glabriflorus var. glabriflorus, Geum canadense × G. laciniatum = G. ×cortlandicum, Juncus scirpoides var. compositus, J. vaseyi, Ludwigia polycarpa, Lycopus americanus ssp. laurentianus, Phegopteris excelsior, Spiranthes arcisepala, S. bightensis, S. incurva, S. odorata, S. sheviakii, Streptopus amplexifolius × S. lanceolatus = S. ×oreopolus, Trillium cernuum × T. erectum, Viola baxteri, V. communis, V. emarginata, and V. latiuscula. Three New York native taxa are now considered to represent two taxa each in the state. These are Ranunculus longirostris and R. trichophyllus for Ranunculus aquatilis var. diffusus, Solidago uliginosa var. peracuta and S. uliginosa var. uliginosa for Solidago uliginosa, and Viola blanda and V. incognita for Viola blanda. One species (Poa interior) previously thought to be native in the state is no longer considered part of the flora. Information regarding an additional four rare native species (Carex decomposita, C. merritt-fernaldii, Muhlenbergia capillaris, and Vahlodea atropurpurea) is provided.

Theodore C. Baim was an amateur botanist who spent most of his adult life documenting and collecting the flora of Schenectady County, New York, between 1937 and 1990. We have transcribed his handwritten flora to serve as a baseline for future floristic work in the county. We also examined and transcribed the label data from thousands of specimens he collected throughout the county and documented in his flora and confirmed their presence in herbaria. Even though it is the second smallest county in the state outside of New York City (after Rockland County), Schenectady County has a very diverse landscape from pine barrens in the east to a black spruce-tamarack bog in the west. It also has a long history of disturbance by farming and urbanization, as well as important transportation corridors, which have resulted in a flora with 29% exotic species. The vouchered vascular flora consists of 1,222 taxa within 466 genera and 133 families. The five largest families are the Asteraceae, Cyperaceae, Poaceae, Rosaceae, and Fabaceae. The largest genera are Carex, Viola, Solidago, Salix, and Symphyotrichum. Twenty species are listed as endangered, threatened, or rare, but some have not been seen in decades. We encourage others to check on Baim's unvouchered observations and literature citations to add to the flora so it can be updated to understand trends and changes.

This paper presents the native vascular plant flora of New York City (Bronx County, Kings County, New York County, Queens County, and Richmond County), New York. The findings are based on a review of the published literature, specimen databases, and analysis of herbarium specimens. The flora comprises 152 families, 512 genera, and 1,456 species (plus 38 hybrids and 33 additional subspecific rank taxa). Carex is the largest genus with 125 species, followed by Viola with 26 species and Symphyotrichum with 26 species. The results are compared to the most recent comprehensive floristic treatments for New York State. Twelve taxa are additions to the New York flora and 174 taxa are new county records.

The orchids of Long Island have been studied by local botanists for almost 200 years, making it one of the longest, continuous floristic studies in the New World. The island's orchid flora comprises 16 genera and 39 species, plus two hybrids and one additional infraspecific taxon; all but one (Epipactis helleborine) are native. Platanthera is the largest genus with 10 species, followed by Spiranthes with seven species. Twenty of the 42 orchid taxa recorded from Long Island are considered extirpated; of the 20, seven are orchids with northern affinities, suggesting a potential role of climate change. Updated distribution maps are presented for all taxa as well as discussion of recent changes in population dynamics, potential causes of declines in frequency, conservation efforts, and an extensive list of references. Platanthera pallida is treated as a distinct species, possessing unique morphological features distinct from P. cristata, endemic to the Montauk Peninsula of eastern Long Island.

Biodiversity surveys rely on accurate species identification as an important component to address increasing rates of extinction. However, morphology-based identification may be hindered by a lack of taxonomic expertise, especially in the presence of cryptic exotics, taxa that are morphologically indistinguishable from natives. This study applies both taxonomic keys and DNA barcodes to identify two potential cryptic wetland plants in Van Cortlandt Park, Bronx, NY, as part of an ongoing floristic inventory. Samples of the park water lilies (Nymphaea spp.) and cattails (Typha spp.) were collected from different stands between 2018 and 2019 and morphologically recorded. Leaf samples were also used for DNA extraction and sequencing of plastid and nuclear barcodes: rbcL and ITS for the water lilies and trnL-trnF, psbA-trnH, and ITS for the cattails. Both morphological and molecular datasets were compared via phylogenetic analyses to artificial samples composed of idealized morphological keys and published GenBank barcode sequences, respectively. In both approaches, there was strong phylogenetic support for the water lilies as the native Nymphaea odorata rather than the exotic N. alba (BS > 90%; BPP = 1.0), which was previously suggested, and for the cattails as both the native Typha latifolia and exotic T. angustifolia (BS > 90%; BPP = 1.0). There was limited support for tentative hybridization between the park cattails, which separated morphologically similar broad leaf samples between groupings containing the different species. Application of DNA barcodes to this and other such surveys may improve the ability of conservationists and park management efforts to meet biodiversity goals by providing increased confidence in the accurate identification of potentially troublesome species.