Horizontal stems flat on ground, 10--18 X 1--1.6 cm, stems (excluding leaves) thick, 1.8--2.2 mm diam.; leaves monomorphic, spreading, and nearly perpendicular to stem, 6--13 X 0.8--1.2 mm; marginal teeth 3--4 per side, mainly on proximal 1/2. Upright shoots 1(--2) per plant, 13--17 X 0.3--0.7 cm; strobilus 1/2--1/3 total length; leaves initially divergent, then incurved, almost appressed, 5--6 X 0.4--0.8 mm, marginal teeth 0--2 per side. Strobili 5--8 X 0.4--0.9 cm. Sporophylls appressed, incurved, 4--6 X 0.4--0.5 mm, marginal teeth absent. 2 n = 312. Lycopodiella margueritae forms apparently fertile hybrids with the other tetraploid species, L . subappressa . Its hybrids with the diploid L . inundata are sterile, however. Lycopodiella margueritae can be distinguished from L . appressa and L . subappressa by the rather thick and large strobili, 1/3--1/2 the total length of upright shoots, and the more spreading leaves of the strobili and upright shoots.