Epilobium hornemannii Reichenb.
Habitat: Damp rocks, margins of small brooks. [Alpine or subalpine (non-forested, upland)]
Range: Arctic America south to Labrador and Newfoundland, Gaspé, Cape Breton, mountains of Maine, New Hampshire, New York, Colorado, Utah, Nevada and California. Also Greenland, Iceland, Scandinavia, northeast Asia.
Aids to Identification: Hornemann's willow-herb is a matted perennial with slender stems, 0.5-4.5 cm. It usually has five pairs of thin, smooth, slightly toothed ovate leaves 1.5-5 cm long, 0.1-2.5 cm broad, on short petioles. Its flowers have four pink petals, 5-8 mm long. The slender seed pods are sparsely pubescent, 2-7 cm. The seeds, under a magnifying glass, are distinctly pebbled.
Ecological characteristics: Other than its restriction to damp places, usually along streams, very little is known about the ecology of this species.
Phenology: Flowers July - August.
Synonyms: Represented in Maine and New England by ssp. hornemanii. Synonyms include Epilobium alpinum L. var. nutans Hornem.
Known Distribution in Maine: This rare plant has been documented from a total of 6 town(s) in the following county(ies): Franklin, Piscataquis.
Reason(s) for rarity: Disjunct from principal range, possible scarcity of suitable habitat.
Conservation considerations: Populations could be threatened by heavy recreational (hiking) use.