A dichotomous key to Radula in the Pacific Northwest

1a. Plants very large (5+cm long), free from substrate with auriculate dorsal lobe and giant solitary oil bodies ocuppying most of cell lumen. . . . Radula auriculata
1b. Plants smaller, growing close to if not appressed to substrate, oil bodies absent, small or more than 1/cell . . .2

2a. Plants frequently gemmiferous along leaf margins, leafy stems ~1.5 to 2.5mm wide, leaves tightly overlapping. . . Radula complanata
2b. Plants withouth gemmae, leafy stems <1.5mm wide, vegetative leaves usually distant . . . 3

3a. Plant with abundant small shoots emerging from axils of leaves, giving a plumose or feathered appearance to the main shoots . . . Radula obtusiloba ssp. polyclada.
3b. Plants lacking small axillary branches, not plumose, often with linear antheridial shoots of tightly overlapping leaves . . . Radula bolanderi.

Of these species, Radula complanata is by far the most common, known to be epiphytic and epilithic from sea level to montane regions. It is particularly abundant on shrubs and alder.

Radula auriculata seems to be confined to hypermaritime locations north of Vancouver Island. I have seen it growing on seashore logs and shrubs.

Radula obtusiloba ssp. polyclada is described in both the Bryophyte Flora of North America treatment of the genus as well as Godfrey's as being hypermaritime on rock and occasionally trees, but I have seen it 5km inland in relatively dry settings growing on alder and conifer bark.

Radula bolanderi is ambient in moist habitats but so small as to easily avoid notice. It is an epiphyte and seems to have a particular fondness for shrubs.

Posted on Ιανουάριος 19, 2023 0104 ΠΜ by rambryum