Riccia sorocarpa
Distinguishing Features
When present, this occasional species of fine, disturbed soils can grow in large populations of overlapping rosettes up to 2cm wide and composed of bright green-to-purple bifurcating thalli. Closer inspection reveals a deep and pervasive furrow in the thallus, that, in combination with its unadorned and green underside, makes it relatively easy to recognize when mature. At later stages, the upper surface of the plant begins to degrade and rupture such that the black capsules embedded within the thallus reveal themselves and release their spores.
Similar species
Ricciocarpos natans, a species of fallow water and its margins, can also exhibit deep furrows across a rosette-forming thallus, but that species has dark underside marked by elongate black root-like structures. Other species within the genus Riccia have porous upper surfaces (see: R. cavernosa, R. frostii), or are adorned by hairs and scales near the margin of the thallus (R. trichocarpa, R. beyrichiana, R. lamellosa). The deep furrows of R. sorocarpa are likewise lacking in R. glauca and R. hueberiana.
Habitat
Seasonally moist humus over rock outcrops, mineral soil, seepage sites, ephemeral pools, shorelines, pond margins, and disturbed areas in the lowland and steppe zones; infrequent in sw and sc BC.
Associated species
Gemmabryum barnesii, Pottia truncata, Riccia beyrichiana, Riccia trichocarpa, Riccia cavernosa, Pleuridium acuminatum, Philonotis fontana