Summary:
Clavulina castaneipes has few to many, flattened, somewhat palmate grooved branches that are dull tan to leaden gray, on a distinct stem coated with upward pointing, fuscous ferruginous or concolorous spicules, and round or nearly round smooth spores on 2-spored basidia. Petersen distinguishes var. lignicola by the following: growing on wood or bark, stout stem (0.4-0.8cm thick) usually colored like the branches, dull tan or brown, the branches ending bluntly or obtusely, basidia and subbasidial clamp connections that are often observed, and spores averaging 10.1 x 9.3 microns. Var. castaneipes, on the other hand, has a slender stem (0.1-0.4cm thick) that is dull brown, branches that are tan or gray, and end acutely, basidial and subbasidial clamp connections that are rarely observed, and spores averaging 9.8 x 8.5 microns, (although 2 collections have spore size and clamp connections more like var. lignicola), (Peterson(23)).

Odor:
none (Corner(2))

Taste:
mild or slowly somewhat bitter (Corner(2))

Microscopic:
spores 9.6-10.4 x 8.8-9.6 microns (average 10.1 x 9.3 microns) for var. lignicola, 9.2-10.8 x 7.7-9.5 microns (average 9.8 x 8.5 microns) for var. castaneipes, round, nearly round, suboval, to pip-shaped, smooth, thick-walled, with 1 droplet, soon losing droplet in dried specimens; basidia 2-spored, rarely 1-spored, occasionally clamped at base, sterigmata 4-8 microns long, stout, cornute, becoming secondarily septate after spore discharge, the upper part evacuating and collapsing; hymenium when first fertile 30-60(90) microns thick, sometimes thickening when old to at least double the thickness, subhymenium composed of freely branching, usually unswollen cells, thin-walled, rarely with some clamp connections; medullary hyphae of the stem composed of long cells (20-150 x 4-10 microns), often slightly swollen (up to 20 microns), especially around the septa, causing septa to appear oblique, rarely highly swollen (up to 35 microns), colorless, "thin-walled, rather loosely arranged, often with regular patterns of curving or zig-zag throughout much of their length", sparsely branched, with no clamp connections; cortical hyphae "linear, composed of unswollen (rarely slightly swollen) long cells, with pale watery fuscous brown walls slightly thickened" (not more than 0.5 microns), "branching and anastomosing freely throughout their length"; hyphae "often passing from one tissue into another and back, assuming the characteristics of the surrounding cells"; hispid fascicles of hyphae in the stem "composed of the latter cell type, with some swollen cells in the center, depending on the size of the fascicle, these hyphae all unclamped", (Petersen)

Notes:
C. castaneipes has been found in BC, MA, Borneo, and Zimbabwe, (Corner(3)), widely distributed in USA, NS, Japan, and Singapore, (Corner(2)). Var. lignicola collections were examined from BC, WA, and OR, and var. castaneipes collections were examined from MA, NC, NY, Japan, and Singapore, (Petersen). Clavulina castaneipes also occurs in CA (Castellano), and CT, PA, and VA, (Coker).

Synonyms and Alternate Names:
Leptoglossum retirugum (Bull.) Ricken