1 Stems prostrate, the leaves on the upper and lower side differentiated; rhizophores borne throughout the length of the stem; leaves borne in pseudowhorls of 8

1 Stems erect or ascending, the leaves not differentiated; rhizophores borne only on rhizomatous stems or at the base of aerial stems; leaves borne in pseudowhorls of 4, 5, or 6.

..2 Apical hair-tip of the leaves twisted-contorted, 1.2-1.7 mm long (sometimes deciduous); strobili 3-6 mm long, 1.5-2 mm wide; leaves 0.15-0.3 mm wide, the marginal cilia absent, toothlike, or as much as 1/6 as wide as the leaf blade; budlike “arrested” branches present

..2 Apical hair-tip of the leaves straight, 0.3-1.4 mm long (sometimes deciduous); strobili (5-) 10-35 mm long, 1-1.5 mm wide; leaves 0.2-0.45 mm wide, the marginal cilia 1/4-1/3 as wide as the leaf blade; budlike “arrested” branches present or absent.

....3 Stems mostly creeping or turned up at the apex, forming mats 1.5-4 cm high; rhizome or rhizomatous stem absent; aerial roots present all along the stems; budlike “arrested” branches absent

....3 Stems mostly erect or ascending, forming compact clumps usually > 4 cm high; rhizome or rhizomatous stem present; aerial roots present only at or near the base of the erect stems; budlike “arrested” branches present.

......4 Leaves of the underground (rhizomatous) stems not scalelike; rhizophores mostly aerial; sporophyll base pubescent; leaf and sporophyll apices often pubescent

......4 Leaves of the underground (rhizomatous) stems scalelike; rhizophores mostly subterranean; sporophyll base glabrous; leaf and sporophyll apices glabrous.

........5 Leaves mostly tightly appressed; leaf bases conspicuously pubescent; strobili distinctly larger in diameter than the subtending stem; sporophyll apex often recurved