Clematis occidentalis (Hornem.) DC.
Habitat: Rocky (often calcareous slopes) and open woods. [Rocky summits and outcrops (non-forested, upland); Non-tidal rivershore (non-forested, seasonally wet); Hardwood to mixed forest (forest, upland)]
Range: Canada to Virginia and west to Iowa.
Aids to Identification: Purple clematis is a climbing vine closely related to the garden variety of clematis, or virgin's bower. Its light green leaves are divided into 3 oval leaflets, on long stalks which often climb and twine to a height of 3 m. The flowers, arising from the leaf axils, are bluish-purple, 5-8 cm across, with 4 thin, almost translucent, sepals (often called petals). The flowers are followed by tufts of silvery, feathery fruits.
Ecological characteristics: Ecological relationships in Maine are not well known.
Phenology: Flowers in May.
Synonyms: Formerly known as Clematis verticillaris DC. Maine population are represented by C. occidentalis var. occidentalis
Known Distribution in Maine: This rare plant has been documented from a total of 26 town(s) in the following county(ies): Androscoggin, Aroostook, Franklin, Kennebec, Knox, Oxford, Penobscot, Piscataquis, Somerset.
Dates of documented observations are: 1891, 1898, 1904, 1907, 1916, 1917, 1933, 1938, 1939, 1943, 1946, 1953, 196 , 1974 (2), 1979, 1981, 1982 (2), 1985, 1988, 1990, 1991, 1993, 1999 (3), 2001 (2), 2002
Reason(s) for rarity: Natural scarcity of suitable (i.e. calcareous) habitat. Scarce throughout its range.
Conservation considerations: Typically occurs in small populations that can be subject to random fluctuations or localized disturbance events. Known populations are all either at forest edges or in the open, indicating that the plant does not do well under heavy forest cover.