Huperzia appressa (Desv.) A. & D. Löve
Habitat: Damp or mossy rocks, cool woods, bare mountains. [Rocky summits and outcrops (non-forested upland). Alpine or subalpine (non-forested upland)].
Range: Greenland to southern Appalachian mountains.
Aids to Identification: Firmosses are recognized by their evergreen upright shoots, dichotomous branching and the presence of spores in the leaf axils and gemmae (small 6-leaved plantlets) in the apical portion of the plant. Huperzia appressa is very similar to H. selago (ranked S1 in Maine) and the two are very difficult to tell apart. H. appressa occurs in exposed, harsh environments in alpine settings, whereas H. selago occurs in boreal, hydric environments including ditches, pondshores and other moist areas, but not in alpine environments. H. appressa has dimorphic leaves (trophophylls): leaves towards the base of the plant are longer and spreading more so than the leaves in the apical portion of the plant. H. selago has monomorphic leaves.
Ecological characteristics: Huperzia appressa is restricted to Maine's highest mountains and a few coastal islands. Hybridization with H. selago is common and the hybrid Huperzia x josephbeitelii A. Haines is frequently encountered above treeline.
Phenology: Sporates in summer.
Family: Huperziaceae (formerly in Lycopodiaceae)
Synonyms: Huperzia appalachiana Beitel & Michel; Huperzia selago (L.) Schrank & Mart. ssp. appressa (Desv.) D. Löve; Lycopodium selago L. var. appressum Desv.; Lycopodium selago L. ssp. appressum (Desv.) Hultén; Urostachys selago (L.) Herter var. appressus (Desv.) Herter ex Ness.
Known Distribution in Maine: This rare plant has been documented from a total of 14 towns in the following counties: Franklin, Hancock, Knox, Oxford, Piscataquis, Somerset.
Reason(s) for rarity: Alpine habitat is scarce.
Conservation considerations: Hikers should stay on trail and avoid trampling alpine vegetation.