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Species Information
Summary: Features include small ascomycete cups with external hairs and orange-yellow to orange spore-bearing upper surface, growth on living branches of Douglas-fir, and microscopic characters including relatively small ascospores. The description is derived from Seaver(2) except where noted.
Lachnellula pseudotsugae was described as Dasyscypha pseudotsugae and examined from BC, OR, and CA (Hahn(2)). There are collections from BC at the Pacific Forestry Centre.
Upper surface: 0.1-0.35cm across, at first spherical and closed, "opening in a roundish form, the margin incurved, urn-shaped, becoming widely expanded and discoid under moist conditions, laterally compressed when dry"; spore-bearing upper surface light orange-yellow to orange
Flesh: waxy-fleshy
Underside: whitish (Hahn(2))
Microscopic: ascospores 4-7 x 2-4 microns, elliptic to fusoid, uniseriate; asci 8-spored, reaching a length of 50-60 microns and a width of 4-5.4 microns, clavate; paraphyses filiform [thread-like], slightly swollen in upper part; hairs 3-3.5 microns wide, cylindric with obtuse ends, hyaline-white, minutely roughened; conidia 2.4-4 x 1.8-3 microns, elliptic, colorless, produced on the ends of simple, or branched conidiophores; conidial stage "consisting of waxy-fleshy, light-buff stromata with labyrinthiform cavities in which the conidia are borne and from which they exude in a droplet or tendril", (Seaver), paraphyses "outranking asci, filiform, of even diameter, septate, not swollen or only slightly so toward the tip with obtuse extremities, minutely guttulate"; exterior hairs 3-3.5 microns wide, "persistent, minutely roughened, hyaline, thin-walled, cylindrical with obtusely rounded extremities, septate, cells short", (Hahn(2))
Habitat / Range
scattered, or closely grouped, forming cankers on living branches of Pseudotsuga menziesii (Douglas-fir), (Seaver), on living branches and trunks of Pseudotsuga menziesii, (Hahn(2))
Similar Species
Lachnellula ciliata (G.G. Hahn) Dennis, has larger spores and is said by Haines(1) to be the most common Lachnellula on Douglas-fir. In his Master''s thesis that included Lachnellula spp. of western Washington, he does not mention L. pseudotsugae by name though he adds that a similar species has been described which is the cause of cankers of Pseudotsuga "but no material was seen for comparison". Dasyscyphus ellisianus (Rehm) Sacc. is an eastern North American species found to be associated with cankers on Douglas-fir among other species by Hahn(4), but at that time (1934) it was not found west of Texas.
