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

Species description:
Genus name referring to the Adam's apple-like swelling at the neck of the sporangium. Species named in honour of G. Wahlenberg, a Swedish botanist of the 19th century who collected the original specimen.

Reproduction:
Sporophytes frequent, reddish-brown when mature, with bright red-brown peristome teeth.

Distinguishing characteristics:
The sub-sheathing leaves, their remarkable contortion when dry, the sporangia with very red-brown peristome teeth and distinct knob in the neck, and the usual habitat on logs in perennially flooded areas are useful features.

Habit:
Forming pale green, yellow-green to brownish-green, short turfs. Leaves sheathing at base and contorted when dry.

Similar Species:
O. virens has recurved leaf margins and enlarged cells at the lowermost margin of the leaf while O. wahlenbergii lacks these features visible with a hand lens. O. wahlenbergii usually has somewhat clasping leaf bases while O. virens lacks them. See also notes under Kiaeria starkei.