Greek rhytis, wrinkle, and opsis, appearance, having rugose leaves as does Rhytidium

J. R. Rohrer

Plants prostrate to ascending and hooked at tips; growth monopodial. Stems irregularly and remotely branched; paraphyllia dense, branched from a 1--2-seriate base into 1-seriate filaments. Stem leaves crowded, erect to spreading, falcate-secund, ovate to lanceolate, strongly plicate, rugose in lower acumen, not decurrent; margins serrulate at apex, otherwise minutely toothed to entire; apex gradually acuminate; costa double, extending 1/4--1/2 leaf length; cells smooth; alar cells ± differentiated. Branch leaves smaller, otherwise similar to stem leaves. Capsule horizontal; operculum conic; exostome teeth irregularly cross-striolate to somewhat reticulate proximally on exterior surface; endostome segments with narrow perforations along keel.

Species 1 (1 in the flora): restricted to western North America.

Lower Taxon

• Rhytidiopsis robusta (Hooker) Brotherus

Related Synonym(s):

• Hypnum robustum Hooker = Rhytidiopsis robusta (Hooker) Brotherus