E-Flora BC: Electronic Atlas of the Flora of British Columbia

Species description:
Genus name denoting wrinkled, in reference to the leaves. The species name, meaning transversely wrinkled, further emphasizes the point.

Reproduction:
Sporophytes unknown in British Columbia. The plants are brittle when dry, thus the fragments undoubtedly serve in propagation.

Comments:
It is rather surprising that this species shows such a wide distribution, especially when sporophytes are so rare. It remains a mystery, therefore, what reproductive devices this moss possesses that allow it to be dispersed from one locality to another.

Distinguishing characteristics:
The leaves with a single midrib and wrinkled surface, plus the regular side branches of many shoots, and the dry, usually open, habitat, usually in calcium-rich areas, are useful features.

Habit:
Forming stiff, golden brownish-green to yellow-green, mats of reclining to suberect, interwoven shoots.

Similar Species:
Rhytidium rugosum is superficially similar to Rhytidiopsis robusta but the leaves have a single midrib rather than double as in Rhytidiopsis. Branching in Rhytidium is usually regular, at least in some plants, while in Rhytidiopsis branching is very irregular. Rhytidium usually occurs in dry, open sites while Rhytidiopsis is a forest species, reaching great abundance in humid, subalpine conifer forests. See also note under Rhytidiadelphus triquetrus.