Canby's Cowbane Tiedemannia canbyi (J.M. Coulter & Rose) M.A. Fiest & S.R. DownieG2 (Globally rare)  -  Endangered (MD)  -  S1 (Highly state rare)  -  Vulnerable  Synonyms: Canby's Dropwort, Oxypolis canbyi.

Status:

Canby's Cowbane is a globally rare native plant that in Maryland is restricted to only one population on the Eastern Shore where the species reaches its northern limits. According to NatureServe, "Oxypolis canbyi is native to the Coastal Plain from southwestern Georgia through South Carolina to southeastern North Carolina, and from eastern MD to (historically) Delaware. Approximately 40 occurrences are believed extant, mostly in South Carolina and Georgia, with an additional 16 occurrences considered historical or of unknown status. There are likely over 10,000 total plants, as at least three Georgia occurrences have "thousands" of plants, and at least four South Carolina occurrences are described as "very large." Other sites have fewer plants. This species' herbaceous wetland habitats - characterized by long periods of inundation and little canopy cover - have declined significantly from historical levels due to drainage and conversion to pasture, farmland, and pine plantations. This threat continues to some extent presently. Habitat degradation is the other major threat to this species, primarily resulting from hydrological alterations and/or fire suppression, both of which can alter successional patterns to the detriment of this species. Water table-lowering activities in the general vicinity of sites can still constitute significant hydrological alteration, such that protecting the sites themselves may be insufficient to ensure persistence. A significant proportion of known occurrences are described as declining in habitat quality and/or population size; many require active management." MD DNR says that Maryland's one location for this globally imperiled plant is found in a Delmarva Bay. Heavy management by various agencies including the Nature Conservancy and MD DNR have brought Maryland's Canby's Cowbane population back from the brink of extirpation. According to NatureServe, "Between 1986 and 1988 [Maryland's population] declined from 100-200 to 7 plants...The Maryland occurrence appeared to be fluctuating but not necessarily declining in 1993-2001 monitoring, following reintroduction of plants (from the population) propagated ex situ. NatureServe goes on to say that the, "Maryland populations are now fluctuating between 14 and 82 plants over nine years of detailed monitoring."

There are 2 records in the project database.

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Canby's Cowbane blooming in Queen Anne's Co., Maryland (8/25/2013). Photo by Jim Brighton. (MBP list)

Canby's Cowbane in Queen Anne's Co., Maryland (8/25/2013). Photo by Jim Brighton. (MBP list)


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