''Tiedemannia canbyi'' (syn. ''Oxypolis canbyi'') is a rare species of flowering plant in the

carrot family Apiaceae or Umbelliferae is a family of mostly aromatic flowering plants named after the type genus '' Apium'' and commonly known as the celery, carrot or parsley family, or simply as umbellifers. It is the 16th-largest family of flowering plan ...

known as Canby's dropwort and Canby's cowbane. It is native to the southeastern United States, where it occurs on the

Atlantic coastal plain The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth#Surface, Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Afr ...

from North Carolina to Georgia, as well as the Chesapeake Bay area. It is threatened by the loss of the wetland habitat in which it grows.''Oxypolis canbyi''.
The Nature Conservancy. It is a federally listed

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

of the United States.

Description

This rhizomatous perennial herb grows up to 1.2 meters in maximum height. The narrow, hollow leaves resemble quills. The inflorescence is a compound umbel of many small flowers with white petals and red-tinged green sepals.USFWS
''Oxypolis canbyi'' Five-year Review.
September 2010. Blooming occurs in August and September,''Oxypolis canbyi''.
Center for Plant Conservation. sometimes lasting until October. The plant has a scent similar to dill. The stems extend along the ground as

stolon In biology, stolons (from Latin '' stolō'', genitive ''stolōnis'' – "branch"), also known as runners, are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external s ...

s, rooting at nodes. It can then produce a colony of many erect stems all belonging to one plant, spreading vegetatively.

Ecology

The larva of the black swallowtail butterfly (''Papilio polyxenes asterius'') feed on the plant. They eat the stem, separating the inflorescence and sometimes preventing sexual reproduction; however, the plant more often reproduces asexually via cloning.

Conservation status

There are about 53 documented populations of this plant, mainly in South Carolina and Georgia. There is one population each in Maryland and North Carolina. The species has been extirpated from Delaware. Most populations are small. The plant grows in a variety of wetland habitat types, including

bay A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, a lake, or another bay. A large bay is usually called a Gulf (geography), gulf, sea, sound (geography), sound, or bight (geogra ...

slough Slough () is a town and unparished area in the unitary authority of the same name in Berkshire, England, bordering west London. It lies in the Thames Valley, west of central London and north-east of Reading, at the intersection of the M4 ...

s, wet savannas, and ponds. Other plants in the habitat may include ''

Ilex myrtifolia ''Ilex myrtifolia'', the myrtle dahoon or myrtle-leaved holly, is a species of holly native to the Southeastern United States The Southeastern United States, also referred to as the American Southeast or simply the Southeast, is a geograph ...

'', '' Nyssa biflora'', '' Taxodium ascendens'', '' Pinus serotina'', ''

Stillingia aquatica Stillingia aquatica, known as water toothleaf and corkwood, is a flowering shrub in the genus ''Stillingia'' that grows in the Southeastern United States in parts of Georgia, Florida, Alabama, and South Carolina. It is in the spurge family, ''Eup ...

'', '' Rhynchospora tracyi'', ''

Rhynchospora inundata ''Rhynchospora'' (beak-rush or beak-sedge) is a genus of about 400 species of sedges with a cosmopolitan distribution. The genus includes both annual and perennial species, mostly with erect 3-sided stems and 3-ranked leaves. The achenes bear ...

'', '' Manisuris rugosa'', ''

Rhexia aristosa ''Rhexia aristosa'' is a species of flowering plants in the Melastomataceae known by the common names awned meadowbeauty and awnpetal meadowbeauty. It is native to the eastern United States, where it occurs on the coastal plain from New Jersey to ...

'', ''

Polygala cymosa ''Senega cymosa'', the tall pinebarren milkwort, is a species of flowering plant in the family Polygalaceae. It is endemic to the United States. References Polygalaceae {{Polygalaceae-stub ...

'', ''

Pluchea rosea ''Pluchea'' is a genus of flowering plants in the tribe Inuleae within the family Asteraceae. Members of this genus might be known as camphorweeds, plucheas, or less uniquely fleabanes. Some, such as ''P. carolinensis'' and ''P. odorata'', are ca ...

'', ''

Lobelia boykinii ''Lobelia boykinii'' is a species of flowering plant in the bellflower family known by the common name Boykin's lobelia. It is native to the eastern United States, where it occurs from Delaware to Florida. There is also a disjunct occurrence in ...

'', and '' Hypericum denticulatum''. The main threat to this rare species is the destruction and alteration of its habitat. Wetlands across the coastal plain of the southeastern US have been dredged, drained, and used for agriculture, including silviculture operations. This process has altered the water regime, both on the surface and in the groundwater table, which in turn has affected the flora. In some cases,

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

s have invaded areas where they were naturally excluded in the pristine habitat. The dropwort grows best in open, unshaded areas that have no canopy. Conservation activities have included the removal of shrubs and trees, including

sweetgum ''Liquidambar'', commonly called sweetgum (star gum in the UK), gum, redgum, satin-walnut, or American storax, is the only genus in the flowering plant family Altingiaceae and has 15 species. They were formerly often treated in Hamamelidaceae ...

(''Liquidambar styraciflua'') and persimmon (''Diospyros virginiana''), that had been encroaching on the wetland and shading out the herb layer.

References

{{Taxonbar, from1=Q50876310, from2=Q7116112 canbyi Flora of the Southeastern United States Plants described in 1900