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1 Leafy stems erect or pendant, simple or dichotomously branched, the ultimate branches vertically oriented; sporophylls like the sterile leaves or only slightly reduced, in annual bands along the stem; vegetative reproduction absent or by leafy gemmae near the stem apex
1 Leafy stems prostrate or erect, if erect then generally branched, the ultimate branches spreading (horizontal) or ascending; sporophylls differing from sterile leaves, either broader and shorter, or more spreading, and aggregated into strobili (cone-like structures) borne terminally on the stems or branches; lacking vegetative reproduction by gemmae.
..2 Leaves herbaceous, pale or yellow-green, dull, deciduous; principal leafy stems creeping (except erect and repeatedly branched in Palhinhaea); rhizome dying back annually to an underground vegetative tuber at apex; spores rugulate; erect fertile shoots in a single dorsal rank; [wetlands, mostly on moist or wet sands or peats]; [subfamily Lycopodielloideae].
....3 Upright shoots repeatedly branched; strobili nodding at the ends of the branches, 4-8 mm long; [known to occur from se. SC southward]
......4 Leaves of the prostrate stems 0.5-1.2 mm wide, ciliate-toothed or not toothed; leaves of the erect stem many, overlapping, spiral; leaves of the strobilus (sporophylls) resembling leaves of the prostrate and upright stems in size and shape; strobilus 10-80 mm long; upright stems 2-15 mm in diameter (including the leaves)
......4 Leaves of the prostrate stems 1.3-2.1 mm wide, not toothed; leaves of the erect stem few, not overlapping, whorled; leaves of the strobilus (sporophylls) much reduced relative to leaves of the prostrate and upright stems, their margins entire to minutely denticulate-fimbriate; strobilus 1.5-9 mm long; upright stems 1.5-3 mm in diameter (including the leaves)
..2 Leaves rigid, bright to dark green, shiny, evergreen; principal leafy stems mainly erect, treelike, fanlike, or creeping (if creeping, then the leaves with elongate, hyaline hair-tips); rhizome perennial, elongate, surficial or subterranean; spores reticulate; erect fertile shoots in 2 dorsolateral ranks; [mostly uplands, in moist to dry soils]; [subfamily Lycopodioideae].
........5 Branches 1-5 mm wide (including the leaves), compressed to quadrangular, with 4 ranks of leaves; branching of strobilus stalks dichotomous
..........6 Strobili borne on elongate, sparsely leafy peduncles borne at the tips of leafy, ascending branches; leaves with attenuate, hyaline hair-tips
............ 7 Erect leafy stems 3-8 mm in diameter (including the leaves), treelike or fanlike, with a definite main axis; leaves acute at the apex; horizontal shoots subterranean, without winter bud constrictions
............ 7 Erect leafy stems 10 mm or more in diameter (including the leaves), branched 1-4 × sub-dichotomously; leaves with a 0.4-1.0 mm long stiff spinule; horizontal shoots at or near the ground surface, with winter bud constrictions