Bucklandiella occidentalis (Ren. & Card.) Bednarek-Ochyra & Ochyra
Synonym: Racomitrium occidentale (Ren. & Card.) Ren. & Card.
Racomitrium heterostichum var. occidentale Ren. & Card.
Special status: NONE
Recognition: This species was treated as a variety of Racomitrium heterostichum by Elva Lawton with good reason: with long hair points they are very similar in the field. In the field, the characteristic yellow olive green of B. occidentalis is usually quite distinctive, readily distinguishable from the blackish, dark green of B. heterosticha. It is a species hard to learn from descriptions but then fairly easy to recognize once a botanist has learned the color differentiation.
However, positive identification depends on leaf anatomy. With bistratose margins consistently present in the distal part of the leaf, it is in the group of species similar to B. sudetica. Its distinctive character is the robust costa which usually has grooves in its distal half. Learning to recognize abaxial costal grooves and ridges of this species is a landmark threshhold for students of this genus. Critical to this taxonomic skill is mastery of sectioning. This is because it is necessary to study a number of leaf sections to get a feeling for the shallow grooves in the costa that characterize the species. Making a determination from a slide with only one or two decent sections is not going to result in acceptable accuracy.
It is important to pay attention to the part of the leaf from which a section has been made. Near the base of leaves all the species of the B. sudetica group may be fairly similar. Here the costa is often quite wide and may occasionally display indentations that appear to indicate grooves on the back of the costa. Only in B. occidentalis are the costal grooves regularly present (if not always present) in the distal half of the leaves. Specimens of B. sudetica with ambiguous costa sections are troublesome. The best clue here is the longer awn of B. occidentalis.
I should point out that development of the bistratose margin is not always strong in B. occidentalis. It is not unusual at midleaf for one side of the leaf to be bistratose while the other margin is unistratose. Bistratosity is typically best developed only in the distal third of the leaf. This is also the best place to look for grooves in the abaxial side of the costa.
For differences between B. occidentalis and the much less common but very similar B. obesa see the discussion under the latter species.
Distribution: On rock and also on wood; widespread in western Oregon at low to middle elevations; apparently more common in the north than in the southern part of the state.
Comments: The ornamentation of the back side of the costa, the abaxial side, is subtle and not always well developed. I have included many more pictures of sections of this species than others to impart a sense of the frequency and nature of this ornamentation. Note that there is a second page of pictures, the Bucklandiella occidentalis Gallery .
Bucklandiella occidentalis; Mt Baker-Snoqualmie National Forest, Washington. R. Lesher 2687a.
Bucklandiella occidentalis; Mt Baker-Snoqualmie National Forest, Washington. R. Lesher 2687a.
Bucklandiella occidentalis; Mt Baker-Snoqualmie National Forest, Washington. R. Lesher 2687a.
Slagle Creek, Jackson Co., Oregon. DHW 9488a.
Bucklandiella occidentalis; Slagle Creek, Jackson Co., Oregon. DHW 9488a.
Bucklandiella occidentalis; Slagle Creek, Jackson Co., Oregon. DHW 9488a.
Bucklandiella occidentalis; Slagle Creek, Jackson Co., Oregon. DHW 9488a.
For more photomicrographs of this specimen, go to Bucklandiella occidentalis Gallery
Guide to Racomitrioideae of Oregon
Created 2007 Northwest Botanical Institute