Guide to Liverworts of Oregon:Scapania irrigua (Nees) Gott. et al.
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Scapania 1 oil bodies several per cell > Scapania 2b marginal teeth evenly spaced or lacking > Scapania 3b dorsal lobe not decurrent > Scapania 5b ventral lobe not decurrent > Scapania 8b marginal cells without thickened cell walls > Scapania 9a 3-5 small oil bodies > Scapania irrigua
Synonym: None.
Special Status: None.
Recognition: Both non-decurrent lobes of this liverwort are quite round, mostly entire, occasionally apiculate where gemmae had been produced. Habitat is a critical field character, along with the non-decurrent leaf lobes. Verification is done by observing oil bodies: 3–4 or 5 small ones in S. irrigua and 2–6 very large ones in S. mucronata. Another species to compare is Scapania scandica, which has frequent gemmae and less quadrangular dorsal lobes. It is not yet included in the key to Scapania; see discussion under that species.
Distribution: Along rivulets in mountains, scattered in the Cascade Mountains.
Comments: Although I've seen this very few times, it is probably relatively frequent, if not common, in subalpine meadow streamsides.
Scapania irrigua, Quaking Aspen Swamp, Lane Co., Oregon. DHW 2199.
Scapania irrigua, shoot apex, dorsal aspect. SE of Mt. Adams, Skamania Co., Washington. D. Stone 8354.15.
Scapania irrigua, leaf insertion, ventral aspect. SE of Mt. Adams, Skamania Co., Washington. D. Stone 8354.15.
Scapania irrigua, detached leaf, unfolded. SE of Mt. Adams, Skamania Co., Washington. D. Stone 8354.15.
Scapania irrigua, leaf margin cells. SE of Mt. Adams, Skamania Co., Washington. D. Stone 8354.15.
Scapania irrigua, midleaf cells. SE of Mt. Adams, Skamania Co., Washington. D. Stone 8354.15.
Scapania irrigua, midleaf cells. Mt. Jefferson Wilderness, Oregon. DHW m2871.