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Page number:379 
Description type:Non-original description 
Description:IRPEX GRISEO-FUSCESCENS (Reichardt) D.A. Reid, Kew Bull. 17:273. 1963. Fig. 7
Basidiocarps annual, effused-reflexed to sessile, single or in imbricate clusters, individual pilei dimidiate to elongated, applanate, usually laterally confluent up to several cm; pilear surface matted-tomentose to almost glabrous near the base, shallowly concentrically sulcate and faintly zonate, Cream Color to Light Buff toward the margin, becoming grayish to Sepia near the base; margin thin and undulate; pore surface drying Tawny Olive to Olive-Brown, pores 2-3 per mm at the margin, dissepiments splitting just behind the margin to form a strongly hydnaceous hymenophore; context duplex, upper layer pale buff, up to 2 mm thick, soft-fibrous, lower layer more firm-fibrous, continuous and concolorous with trama; hymenophore up to 4 mm thick.
Hyphal system dimitic; contextual generative hyphae thin- to firm-walled, with frequent, often closely spaced simple septa, with occasional branching, 2-5 µm in diam; contextual skeletal hyphae thick-walled, nonseptate, rarely branched, 3-6 µm in diam; tramal hyphae similar.
Cystidia abundant, subulate, hyaline, not incrusted, firm-walled, imbedded or projecting, 4-6 µm in diam, difficult to trace back to a basal septum, but commonly over 50 µm long.
Basidia clavate, 4-sterigmate, 17-20 x 4.5-5.5 µm simple-septate at the base. Basidiospores oblong, hyaline, smooth, thin-walled, negative in Melzer's reagent, 4-4.5 x 2-2.5 µm.
RLG 16857, Baptist Church, Hilo, Hawaii, causing a white rot of Trema orientalis. Cunningham (1965) described this fungus as Trichaptum venustum (Berk.) G.H. Cunn. Reid (1963) and Ryvarden and Johansen (1980), however, consider T. venustum to be a synonym of T. byssogenum, which is a quite different fungus with clamped generative hyphae, larger spores, and apically incrusted cystidia. Raabe et al. (1981) listed this fungus from Hawaii as Polyporus vellereus Berk.
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