Guide to Liverworts of Oregon: Riccia trichocarpa M.A. Howe
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Riccia 1 terrestrial > Riccia 2a marginal projections present > Riccia 3a cilia very long > Riccia 3
Synonym: None.
Special Status: None.
Recognition: This species has the longest thallus spines of any in Riccia, marginal and centered over the sporangia in mature specimens.
Distribution: On seasonally moist soil; California to Lane County, Oregon.
Comments: The characteristic spines originating over sporangia are not seen before sporangia are mature. The drawings of spores by M.A. Howe, 1899, are remarkably accurate, closely matching the SEM images prepared (and used with permission) by Bill Doyle. Mature spores are black and so opaque that no details are discernable at high magnification under transmitted light in optical microscope observation.
Riccia trichocarpa. Coarsegold, Madera Co., California. Photo: S. Renkes 4 March 2023.
Riccia trichocarpa. Coarsegold, Madera Co., California. Photo: S. Renkes 4 March 2023.
Wagontire Rock, Monterrey Co., California. DHW m1235a.
Riccia trichocarpa. Spores are from type, D.H. Campbell, Stanford University, Santa Clara Co. Illustration: M.A. Howe 1899, plate 88.
Riccia trichocarpa. Spores in reflected light. Bloomberg City Park, Eugene, Lane Co., Oregon. D.Thomas 13817.
Riccia trichocarpa. Proximal aspect. East of Springville, Tulare Co., California. W.T. Doyle 8330 (UC).
Riccia trichocarpa. Distal aspect. East of Springville, Tulare Co., California. W.T. Doyle 8330 (UC).
Riccia trichocarpa. Side view. East of Springville, Tulare Co., California. W.T. Doyle 8330 (UC).