Guide to Liverworts of Oregon: Riccardia multifida (L.) S. F. Gray
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Riccardia 1b oil bodies present in many cells > Riccardia 2b oil bodies absent from most epidermal cells > Riccardia 3a unistratose margin 2-3 cells wide > Riccardia multifida
Synonym: None.
Special Status: None.
Recognition: This is characterized by a thin, narrow green thallus that is regularly pinnately branched. In most cases the unistratose margin that is two or three cells wide will serve to identify the species; it is monoicous and has oil bodies in less than 20% of the marginal and epidermal cells. Most easily confused with R. chamaedryfolia, which usually has a similar branching pattern but lacks the unistratose margin and has oil bodies in over 80% of its epidermal cells.
Distribution: On sticks, sandy soil, or gravel in seepy places or close to streams; widespread in the region.
Comments: About as common as R. chamaedryfolia and growing in similar habitats, not easily distinguished in the field but easily told apart when fresh by examining oil bodies under a microscope. The unistratose margins are distinctive but not always well developed.
Riccardia multifida, King County, Washington. DHW m1947.
Riccardia multifida, Yaquina Head, Lincoln County, Oregon. DHW m2243.
Riccardia multifida, wing margin of thallus, Wolf Creek, Lane County, Oregon. DHW 6772.