TYPE. SWEDEN. Varmland, Brattfors par., Bålbäcken, ~2 km S of Lake Bålen, on wood of standing dead Picea sp., 59°37'N, 14°07'E,130 m elev., 17.VIII.1983, L.-E. Muhr 6684 (IMI 288326, holotype; S, isotype).
Life form. Non-lichenized, allied fungus.
Description. [Modified from Sutton & Muhr (1986)] Thallus absent; photobiont absent; ascomata absent. Mycelium immersed, thin-walled, branched, septate, hyaline, 2-4 μm wide, concentrated in the outer broken xylem vessels of the wood. Conidiomata eustromatic, sporodochial, punctiform, superficial, circular to ellipsoid, solitary or sometimes 2-5 aggregated, when young white, with age becoming smoke grey to grey olivaceous from the margin towards the center, dry, pulverulent, up to 400 μm diam. x 100 pm high, consisting of a base of loosely aggregated hyaline cells and hyphae from which ascending branches bear conidia at different levels. Conidiophores hyaline, septate, irregularly and repeatedly branched, towards the base 2.0- 2.5 μm wide becoming progressively wider, up to 10 μm wide towards the apex, individual cells markedly constricted at the septa, contents reduced, cell walls 1-2 μm thick, formed from the basal cells of the conidiomata. Conidiogenous cells integrated, apical, lateral or intercalary, hyaline, smooth, thick-walled, globose to ellipsoid, up to 12 x 10 μm, producing 2-3 separate conidia from different loci. Conidia to 35 x 22-35 μm, hyaline when young, becoming pale brown at the base when mature (this giving the conidiomata the deeper pigmentation with age), smooth, flabelliform to palmate, consisting of a truncate basal cell, 3-5 x 3-4 μm from which usually 2 dichotomous branches arise, each of which branches again, either dichotomously each to form 2 more branches, or irregularly, finally producing a conidium with 4-10 arms; arms 4-9-distoseptate, with reduced cell lumina, straight or slightly bent, obtuse at the apices, 13-20 x 3.5-5 μm.
Substrate and habitat. Lignicolous and corticolous in shaded and humid forests.
Distribution. Scattered pantemperate (Europe, Turkey, Kamchatka, Pacific Northwest and eastern North America; in North Carolina found in the Blue Ridge ecoregion.
Literature
Sutton, B.C. & L.E. Muhr (1986) Cheiromycina flabelliformis gen. et sp. nov. on Picea from Sweden. Nordic Journal of Botany6(6): 831-836 (original description).