An Illustrated Flora of the Northern United States, Canada and the British Possessions/Lycopodiaceae

Sporophyls not closely associated in terminal spikes. Stems rigidly erect; leaves ascending, nearly uniform. Stems ascending; leaves spreading or deflexed, longer or shorter in alternating zones. Leaves distinctly broadest above the middle, there usually erose-denticulate. Leaves linear or nearly so, entire or minutely denticulate. Sporophyls closely associated in terminal spikes. Sporophyls similar to the foliar leaves in form and texture; Sporanges subglobose. Sporophyls linear-deltoid, mostly entire; plants small. Sporophyls linear to lanceolate from a broader base; plants larger. Peduncles slender, the leaves incurved and mostly appressed; spikes slender, the sporophyls less than 3" long, abruptly subulate, incurved. Peduncles very stout, the leaves more numerous and close, mostly ascending, not incurved; spikes stout, the sporophyls more than 4" long, attenuate, ascending, spreading or reflexed. Sporophyls bract-like, very unlike the foliar leaves; sporanges reniform. Stems with numerous erect or assurgent leafy aerial branches, the spikes terminal upon some of these. Leaves of the ultimate aerial branches in 5 or more rows. Main stem creeping deep in the ground; aerial branches few, tree-like. Main stem prostrate, or (in no. 10) a little below the surface; aerial branches numerous, not tree-like. Leaves of the ultimate aerial branches in 5 rows. Leaves of the ultimate aerial branches in more than 5 rows. Spikes solitary, sessile. Spikes one or several, on elongate peduncles. Leaves of the ultimate aerial branches in 4 rows. Spikes sessile upon leafy branches. Spikes borne upon bracteate peduncles, these terminal upon leafy branches. Leaves of the ultimate aerial branches adnate considerably more than half their length. Ultimate aerial branches conspicuously flattened; leaves of the under row greatly reduced, minute, deltoid-cuspidate. Ultimate aerial branches narrower and less flattened; leaves of the under row scarcely reduced, acicular. Leaves of the ultimate aerial branches adnate about half their length or less. Stems without leafy aerial branches, the elongate peduncles arising directly from the prostrate stem.