Diphasiastrum sitchense (Rupr.) Holub
Habitat: Barrens, mountain slopes and summits, and open thickets. [Alpine or subalpine (non-forested, upland)]
Range: Labrador to Alaska, south to northern New England, and northern New York.
Aids to Identification: Alaskan clubmoss is very similar in appearance to the hybrid Diphasiastrum x sabinifolium but they can be distinguished by the following features: Alpine clubmoss has leaves of uniform length arranged in five ranks, and the sterile branchlets are not flattened. Identification can be further complicated by the fact that the growth form varies widely with the habitat among clubmoss species. Plants growing in the sun are more compact, shorter, more upright, while those in woodlands are taller and more spreading.
Ecological characteristics: In Maine, this clubmoss is typically found in open, moist, subalpine areas.
Phenology: Sporulates mid-July - September.
Synonyms: Diphasiastrum sitchense (Rupr.) A. & D. Löve; Lycopodium sabinifolium Willd. var. sitchense (Rupr.) Fern.; Lycopodium sitchense Rupr.
Known Distribution in Maine: This rare plant has been documented from a total of 7 town(s) in the following county(ies): Aroostook, Franklin, Oxford, Piscataquis, Somerset.
Reason(s) for rarity: At southern limit of range; habitat naturally scarce.
Conservation considerations: A known population on Mt. Katahdin, could become threatened by heavy hiking use, but appears to be persisting for now.