This was a new species to me, but one I was hoping to find on The Cliff, since it is known to be lithophytic (living on rocks). It is a small but pretty liverwort, and fairly easy to identify with a hand lens.
Description-Scapania are usually fairly easy to identify to genus, because the leaves have toothed, rounded dorsal and ventral lobes that are unequal in size, with the dorsal lobe being much smaller, and they are lacking in underleaves. On S. americana the teeth are spaced evenly, and are the same distance apart on both dorsal and ventral lobes. Both dorsal and ventral lobes have bases that run down the stem (decurrent), and the base of the dorsal lobe is folded over (ampliate). An important identification tool is that Scapania americana is almost always found on rock (although David Wagner reports seeing it once on Big-leaved Maple). It is pale green to yellow green, usually prostrate and unbranched, and the shoots are seldom more than 3cm long.
Similar species–Scapania bolanderi has teeth on the dorsal lobe spaced almost twice as far apart as those on the ventral lobe, and is almost always found on wood or soil. Several other Scapania spp. are more or less aquatic, and the ones that aren’t don’t have decurrent dorsal lobes. Diplophyllum spp. have similarly lobed leaves, but they are not toothed.
Habitat– Low to middle elevations on seasonally wet rock, and on sand near the coast.
Range– West of the Cascades from BC to California
Reproductive timing– Spring to early summer
Etymology of names– Scapania is Greek for spade, and refers to the flattened, spadelike perianth. Not exactly sure about americana. It is strictly a North American species, but it is also strictly a west coast species, and its range extends through Canada to Alaska.