Diphasiastrum Holub. Flat-branched Clubmoss, Running Cedar.
A genus of about 15-20 species, mostly north temperate and subarctic. This group has often in the past been treated as Lycopodium section Complanata (Øllgaard in Kramer & Green 1990, Øllgaard 1987, Wikström & Kenrick 2000).
ID notes: Diphasiastrum is similar in overall appearance to Dendrolycopodium. Both genera have horizontal rhizomes (on or below the ground surface), bearing vertical stems at intervals, and each vertical stem bears sterile branchlets and fertile branchlets. The sterile branchlets are horizontal to ascending, and branch dichotomously (in Ys), while the fertile branchlets are erect and terminate in narrow strobili (cone-like structures) which bear the sporangia. At all seasons, Diphasiastrum is easily distinguished from Dendrolycopodium by its leaves, which are scale-like and tightly appressed to the branches, giving the plant a smooth texture, as opposed to the leaves of Dendrolycopodium, which are needle-like (but only slightly stiff), and which spread away from the branches at acute to right angles, giving the plant a slightly prickly appearance and feel.
Ref: Haines (2003a); Øllgaard In Kramer & Green (1990); Wagner & Beitel (1993) In Flora of North America Editorial Committee (1993b); Wikström & Kenrick (2000). Show full citations.