Summary: Helminthosphaeria clavariarum forms a gray to black coating on Clavulina coralloides (caused by formation of their minute fruitbodies), seeming to reduce branching of the tips of the Clavulina, (Trudell). It is found on fruitbodies of Clavulina coralloides (as C. cristata) and C. cinerea, (Dennis). Black dots may be observed in the coating under a hand lens and are visible in larger digital images. The conidial state, which may be found without perithecia, has been called Spadicoides clavariarum.
Microscopic: spores 10-14 x 6-7 microns, broadly fusiform or one-sided, dark brown, non-septate, uniseriate; asci 8-spored, up to 90 x 8 microns, cylindric, stalked; paraphyses numerous; some hairs tapering to a point, others cylindric and bearing elliptic, 1-septate, brown conidia, (Dennis)
Notes: Helminthosphaeria clavariarum on fruitbodies of Clavulina coralloides has been vouchered from WA (for instance WTU-F-000133 as Clavulina cristata from WA at the University of Washington, by S. Trudell). It is casually reported more widely on sight in the Pacific Northwest including BC, and a parasitized collection of Clavulina coralloides (as Clavulina cristata) from BC is at the Pacific Forestry Centre.
Habitat and Range
SIMILAR SPECIES
It may be difficult to distinguish Clavulina cinerea macroscopically from parasitized collections of Clavulina coralloides. There is an excellent discussion of this problem in Kuo(7). Helminthosphaeria clavariarum parasitizes both species from the base upwards, rendering them gray to black. ''Under a hand lens, the tiny black dots that form the perithecia of the pyrenomycete can be seen'' and under the microscope the differences are obvious. The black dots may be seen on larger digital images. Most Clavulina cinerea fruitbodies, as presented in field guides and on the Internet, ''display grayish to purplish gray (not dark gray or black) colors on the branches and paler surfaces near the base of the mushroom, suggesting that the gray surfaces above do not represent the influence of the parasite, which attacks from the base upward.''. ''However, even if Clavulina cinerea does not (usually) represent parasitization of Clavulina cristata, it may still merely represent a gray and frequently less cristate form or "ecotype" of the latter'', (Kuo(7) with Latin names italicized).
Habitat
on fruitbodies of Clavulina coralloides (as C. cristata) and C. cinerea, (Dennis)