Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to Oregon, east to the Rocky Mountains, northern Great Plains, Great Lakes region, and eastern North America.
Habitat: Moist forests, bog edges and rocky areas, lowlands to subalpine
Spores: May-July
Origin: Native
Growth Duration: Perennial
Conservation Status: Not of concern
Trailing perennial; stems creeping horizontally on substrate or subterranean; upright shoots clustered, mostly unbranched or weakly branched at base, 12-16 mm in diameter, annual bud constrictions abrupt and obvious; lateral branchlets few and same as upright shoots except annual bud constrictions absent; roots emerging from underside of stems.
Leaves spreading to bent backwards, dark green, linear-lanceolate, 5-8 mm long and 0.6-1.2 mm broad, margins finely dentate mostly towards apex, apex sharp-pointed, hair-tip absent.
Strobili solitary and sessile atop upright shoots, 15-30 mm long and 3.5-4.5 mm broad; sporangia reniform; spores reticulate, side at midsection convex.
PNW Herbaria: Specimen records of Spinulum annotinum in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Spinulum annotinum checklist entry
OregonFlora: Spinulum annotinum information
E-Flora BC: Spinulum annotinum atlas page
CalPhotos: Spinulum annotinum photos