Racomitrium canescens (Hedw.) Brid.


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Synonym: Niphotrichum canescens (Hedw.) Bednarek-Ochyra & Ochyra

Special status: NONE.

Recognition: Racomitrium subgen. Niphotrichum species are characerized even from a distance by their pale gray green color with a frosted aspect. The common species in Oregon with this aspect is almost always Racomitrium elongatum. Much less common is R. canescens, which is more abundant in northern boreal regions. Also with a more northern distribution, not yet found in Oregon, is another similar species, R. ericoides. The differences between these species are too subtle to separate them in the field, except for adepts with extensive experience (which I currently lack). Examination of whole leaf mounts under the microscope is necessary; fortunately sectioning leaves is not necessary. This species is characterized by a relatively short costa which is forked in many leaves and which terminates in a broad, caniculate trough. For further discussion, see R. elongatum.

Distribution: Not at all common but widespread in Oregon. I have seen it only from Jackson County, Hood River County, and from Baker County. More common northward, possibly from California (see R. ericoides).

Comments: Although Frisvoll (1983) clearly elucidated the species presently recognized in the Racomitrium canescens group, local botanists have been slow to take up any of them. We have preferred to treat most of these under the broad concept of Racomitrium canescens as used by Lawton (1971). The publication of the Flora of North America, with these species segregated into the genus Niphotrichum, should bring about a change in how we name these plants.The separation of Niphotrichum from Racomitrium s.l. makes the most sense to me. I do not find the other segregates (Bucklandiella, Codriophorus) to be nearly as clearly defined. My preference is to retain them all in the genus Racomitrium, reconizing these segregates at the subgenus rank.

The specimen from Union County appears to be subsp. latifolium C. Jens. It has nonfalcate leaves, chlorophyllose cells reaching the base of the hair point, only moderately spinulose hairpoint tip, and decurrent hyaline strips below the hairpoint. The costa in this specimen frequently ends at 0.5 of the leaf, before it enters the broad costal channel below the awn. Ochyra and Bednarek-Ochyra (2007) point out that the distinction between these two subspecies is blurred in the Rocky Mountains of British Columbia and Washington (probably meaning NE Washington). Both Jackson County specimens (Kofranek 1331; Wagner m0421) tend towards subsp. canescens.


Racomitrium canescens - near Howard Prairie Reservoir, Jackson Co, Oregon. DHW m0421.



Racomitrium canescens var. latifolium - Starkey Experimental Forest, Union Co, Oregon. A. Hardman 4029.



Racomitrium canescens var. latifolium - Starkey Experimental Forest, Union Co, Oregon. A. Hardman 4029.



Racomitrium canescens var. latifolium - Starkey Experimental Forest, Union Co, Oregon. A. Hardman 4029.



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Guide to Racomitrium of Oregon
Created 2007 Northwest Botanical Institute