Much like no. 16 [Lycopodium complanatum L.]; horizontal stems deeply subterranean; erect stems repeatedly and rather irregularly branched, the principal branches commonly at several successive levels, subdichotomous, the ultimate branchlets 1.2-2 mm wide (incl. lvs), appearing narrower than in no. 16, somewhat bluish-glaucous beneath; lvs of the ventral rank 1-1.5 mm, the tip sometimes reaching the base of the next lf; cones mostly 3-4; sporophylls and sporangia a little smaller than in no. 16; 2n=46. Coniferous woods and sandy places; Nf. and Lab. to Man., s. to Md., Va., Ind., and Minn., and in the mts. to S.C., Ga., and Ala.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.