Guide to Liverworts of Oregon: Chiloscyphus pallescens (Ehrh. ex Hoffm.) Dumort.
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Chiloscyphus 1a leaves round, rarely retuse > Chiloscyphus 2b oil bodies more than 2 per cell > Chiloscyphus pallescens
Synonym: Chiloscyphus fragilis (Roth.) Schiffn.
Special Status: None.
Recognition: Medium sized plants with round, nearly horizontally inserted, succubous leaves. This species is indistinguishable from Chiloscyphus polyanthus when dry. The only constant character seems to be the oil body number, more than two per cell in most cells in this species and exactly two in 80% of the cells of Chiloscyphus polyanthos. I think the differences noted in the male bracts could serve as distinguishing characters but further research is needed to confirm this impression. The drawing below shows antheridia in small flaps at the base of otherwise little modified leaves. Androecia of C. polyanthos have been seen with male bracts well differentiated. Since androecia are scarce, the characters of these shoots may not be of great utility even if consistent.
Distribution: Usually found on damp substrates close to water but not actually submerged. See Chiloscyphus polyanthos.
Comments: Although habitat partition is quite consistent, it is not sharp enough to separate C. polyanthos from C. pallescens in that C. polyanthos sometimes grows where it is not submerged 100% of the time. The reciprocal situation seems not to occur, that is, C. pallescens does not occur in strictly submerged situations.
Past keys have emphasized a difference in cell size to differentiate C. pallescens from C. polyanthos; the former usually has larger cells. However, although this character is a good clue, it is not consistent enough to be reliable.
Leaf. Small stream flowing into Sparks Lake between Goose Creek and Falls Creek, Deschutes County, Oregon. DHW m3122.1
Male shoot. Parker Creek, Marys Peak, Benton County, Oregon. DHW m2506.
Antheridia in place. Parker Creek, Marys Peak, Benton County, Oregon. DHW m2506.
Male shoot. Alsea River, Benton County, Oregon. DNW 3185.
Oil bodies. Small stream flowing into Sparks Lake between Goose Creek and Falls Creek, Deschutes County, Oregon. DHW m3122.1
Oil bodies. Small stream flowing into Sparks Lake between Goose Creek and Falls Creek, Deschutes County, Oregon. DHW m3122.1