1 "Paraphyllia present, usually densely inserted on stems and larger branches; costae single, ending above mid-leaf" 2 1 "Paraphyllia absent; plants mostly julaceous; costa weak, or basally flattened and forking into subsidiary costae" 3 2 "Cells strongly prorate; plant plumose and tending to curl into a ball upon drying; branch leaves conspicuously 5-ranked" "Dendroalsia abietina" 2 "Cells smooth; plant plumose or not, never strongly distorted on drying; branch leaves not conspicuously ranked" "Alsia californica" 3 "Cells strongly prorate; costa mostly ending near leaf middle, often distally forked; branches sometimes strongly attenuate with the entire branching system resembling a bird's foot" "Pterogonium gracile" 3 "Cells smooth; costa mostly stronger; branches usually not strongly attenuate" 4 4 "Leaves with costa extending above the leaf middle with its distal portion of costa cloaked with dorsal spines or cristae" "Bestia longipes" 4 "Leaves with costa of various lengths but not cloaked with dorsal spines or cristae" 5 5 "Leaves with costa strong and terete near base but forking distally and disappearing around mid-leaf" "Pseudoleskeella serpentinensis" 5 "Leaves with costa flattened at the base, mostly forked at that base into supplementary costae" 6 6 "Plant julaceous; cell walls little pitted; supplementary costae less than 5 cells long" "Antitrichia californica" 6 "Plant not julaceous; cell walls strongly pitted throughout leaf; supplementary costae much stronger" "Antitrichia gigantea"