- Scientific name: Sclerolepis uniflora
- Species of Greatest Conservation Need (MA State Wildlife Action Plan)
- Endangered (MA Endangered Species Act)
Description
One-flower sclerolepis is a globally rare, vulnerable (G3 rank, NatureServe 2025) delicate, creeping plant in the aster family (Compositae or Asteraceae), which can form extensive mats on pond shores. The linear, stalkless, hairless leaves are 1-2 cm (0.4-0.8 in) long and are arranged in whorls of four to six. The stems reach from 1-4 dm (3.9-15.7 in) in length and are usually unbranched. In autumn, one-flower sclerolepis produces pinkish or flesh-colored flowers borne in a terminal head (a dense cluster of small, stalkless flowers). This inflorescence is 4-15 mm (0.16-0.6 in) wide. The fruit is a 1-1.3 mm (0.04-0.05 in) long, dark brown to black achene (a dry, one-seeded fruit) with whitish ribs.
Golden hedge hyssop (Gratiola aurea) is found in the same habitat as one-flower sclerolepis. While golden hedge hyssop looks similar when immature, it has only two opposite leaves per node and has wider, lanceolate leaves. In addition, mature plants of golden hedge hyssop have showy, yellow, tube-shaped flowers.
Life cycle and behavior
One-flower sclerolepis is a perennial that can spread vegetatively and overwinters as slender, whitish rhizomes (horizontal underground stems which may bear rootlets).
Population status
One-flower sclerolepis is currently listed as Endangered in Massachusetts. There is only one population in the Commonwealth, which was first discovered in 1911. Reasons for the plant's rarity include the plant's limited dispersal capability and the fact that Massachusetts is disjunct from the major portion of the plant's range. One-flower sclerolepis is also considered rare in New Hampshire, Rhode Island, New Jersey, Delaware, Maryland, North Carolina, and Louisiana.
Distribution in Massachusetts
1999-2024
Based on records in the Natural Heritage Database
Distribution and abundance
The documented range of one-flower sclerolepis includes areas near the coast from Alabama and Florida to New Jersey. Disjunct populations occur in Massachusetts and New Hampshire.
Habitat
One-flower sclerolepis is found on sunny pond shores, amongst cobbles or where leaf litter collects, where there is a considerable drop in water level late in the summer. It appears to require protection from wave action; however, it can grow both on beaches and in shallow water. The one current station in Massachusetts is a pond shore habitat, including sandy, gravelly areas among boulders and wet, peaty areas. Associated species include the water milfoils Proserpinaca intermedia and Proserpinaca pectinata, pipewort (Eriocaulon septangulare), golden hedge hyssop (Gratiola aurea), various species of rush (Juncus spp.), and mermaid-weed (Myriophyllum spp.).
Healthy habitats are vital for supporting native wildlife and plants. Explore habitats and learn about conservation and restoration in Massachusetts.
Threats
Threats include shore development, boat and foot traffic, housing and road development leading to siltation and alteration of hydrology, surface water alteration from dams and ditches, water pollution, habitat conversion, road and powerline maintenance activities including herbicide and rutting, recreational activities such as off-road vehicles, sea level rise and salt inundation and invasive species (NatureServe 2025).
Conservation
NatureServe (2025) suggests for this globally rare species that “all occurrences need to be monitored to determine the status of threats, site condition, and abundance of plants and to establish baseline data to develop our understanding of trends and threats. Potential habitat should be surveyed for new populations. Long term protection should be evaluated and considered for exceptional sites.”
References
NatureServe. 2025. NatureServe Network Biodiversity Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.149204/Sclerolepis_uniflora. Accessed 2 May 2025
Contact
| Date published: | May 12, 2025 |
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