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

Warnstorfia exannulata (B.S.G.) Warnst.
ringless hook-moss (warnstorfia moss)

Species Account Author: Wilf Schofield
Extracted from Some Common Mosses of British Columbia

Introduction to the Bryophytes of BC
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Distribution of Warnstorfia exannulata
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Species Information

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Illustration Source: Some Common Mosses of BC

Species description:
Genus name referring to the curved branches, exaggerated by the curved leaves on the stems. Species name based on the absence of a ring of specialized cells (annulus) around the mouth of the sporangium.
Sporophytes occasional, with red-brown setae and dark brown to light brown sporangia. Plants also probably readily fragmented.
Distinguishing characteristics:
The wet habitat, combined with the well defined group of alar cells and the curved leaves with a midrib are distinctive. It is the most common aquatic and wetland species of the genus in the Province.
Loosely to densely interwoven, reclining, dark green to purplish-brown mats of glossy plants.
Similar Species:
D. ftuitans grows in similar habitats, but is less com­mon. It lacks the distinctive alar cells and the leaf apices are generally markedly toothed. Cratoneuron filicinum, which shows obvious differen­tiated alar cells, does not exhibit the strongly curved leaves; the plants also tends to be more obviously pinnately branched. D. crassicostatus also lacks the distinctive alar cells and tends to be confined to calcium­ rich sites; also tends to be more rigid than the rather soft plants of D. exannulatus.

Habitat / Range

In swamps, peatland, seepage sites and submerged to floating in the quiet waters of pools, lake margins and backwaters of water­courses.
World Distribution

Circumpolar in the Northern Hemisphere and scattered in the Southern Hemisphere. In North America extending southward in the east to New York State and Wisconsin; in the west to Arizona.

Synonyms and Alternate Names

Drepanocladus exannulatus (Schimp.) Warnst.
Drepanocladus exannulatus var. alpinus (Grav.) Wijk & Margad.
Drepanocladus exannulatus var. brachydictyon (Renauld) G. Roth
Drepanocladus exannulatus var. exannulatus
Drepanocladus exannulatus var. falcifolius (Renauld) Grout
Drepanocladus exannulatus var. purpurascens
Drepanocladus exannulatus var. purpurescens (Schimp.) Herz.
Drepanocladus exannulatus var. rotae (De Not.) Loeske
Warnstorfia exannulata var. exannulata
Warnstorfia exannulata var. purpurascens (Schimp.) Tuom. & T. Kop.

Taxonomic and Nomenclatural Links

Additional Range and Status Information Links

Additional Photo Sources

General References