Monographs Details: Pelloporus hamatus Romell
Authority: Fidalgo, Oswaldo & Fidalgo, Maria E. 1968. Polyporaceae from Venezuela. I. Mem. New York Bot. Gard. 17 (2): 1--34.
Family:Hymenochaetaceae
Description:Species Description - MACROSCOPIC CHARACTERS. Sporophore: centrally stipitate, of light weight when dry. stipe: long, velutinous, tough, ferruginous-brown, MP-7A12 (Argus Brown), (5.5-)9-13(-16) cm long, 0.4-1.5 cm diam, slightly inflated at the base, pileus: circular, infundibuliform, rigid and brittle, (3-)6-8 cm diam, up to 0.2 cm thick, abhymenial surface: fibrillose to smooth, silky and subshiny, concentrically zonate, slightly sulcate at the depressed center, ferruginousbrown, MP-7A12 (Argus Brown) to MP-15A12 (Burnt Umber). margin: entire, very thin, smooth, slightly paler than the pilear surface, inflexed when dry. context: coriaceous, very thin, up to 1 mm thick, cinnamon-brown, AIP-14G11 (Tortoise Shell), subhomogeneous; with KOH the trama darkens pennanently. tubes: in one single layer, up to 1 m m long, buff brown, MP-12I6 (Powdered Gold) to yellowish brown, MP-13J8 (Clay), poroid surface: dull, yellowishbrown, MP-13J8 (Clay); pores medium, regular, ovoid to subcircular, 2-3(4) per mm, 200-300X (120-) 150-250 µ diam; dissepiments entire, obtuse, 70-200 µ thick. MICROSCOPIC CHARACTERS. Stipe: formed by a variable, broad central core, 2-14 mm thick, of closely aggregated generative hyphae, 6.5-10.5 µ diam, with very regular and slightly thickened walls, frequent simple septa and very few branches, all running parallel; enveloping this central core exists a very regular layer, 600-800 µ thick, of shortly branched generative hyphae, 3-7.5 µ diam, showing no definite orientation, with the endings of the most external ones freely projected, forming an irregular, atypical and loose trichoderm which provides the velutinous aspect to the stipe, pilear surface: a cutis represented by a thin, dark brown layer, about 20-30 µ thick, formed by closely aggregated, dark brown and periclinally oriented generative hyphae, 9-13 µ diam, with dark brown content and many free round endings, context: divided into two layers, according to the orientation of the hyphae. Upper layer with monomitic hyphal system formed by generative hyphae, mostly periclinal, 6.5-10.5 µ diam, with a broad and conspicuous lumen and scarcely branched. Lower layer with dimitic hyphal system formed by generative hyphae showing no definite orientation, 3-6.5 µ diam, narrow lumen and moderately branched; some of the generative hyphae give origin to setal skeletal hyphae, very thick-walled to solid, dark brown, 6-12.5 µ diam, 80-350 µ long with uncinate or more rarely straight tips; tips acute projecting or not into the lumen of the tubes, dissepiments: dimitic; generative hyphae yellowish to yellowish-brown, 3-7 µ diam, with simple crosswalls and branched; setal skeletal hyphae, 6-12.5 µ diam, like the ones observed in the lower part of the context. hymenium: hyphal pegs, cystidia and hymenial setae not present; basidia hyaline, small, 4-sterigmate, subclavate, 5.5-8 µ diam; basidiospores not found. Hymenium frequently interrupted by the projection of setal skeletal hyphae up to 30 µ long; such hyphae formed deep in the dissepiment or in the lower part of the context.

Distribution and Ecology - Distribution. It appears to be a rare species known so far only from the type collection (Mato Grosso State, Brazil). We have seen previously another collection from Amazonas State, Brazil (not reported). Apparently it has never been reported from Venezuela, this being the first record. W e have examined just one collection from VENEZUELA: Bolivar: Chimanta Massif, Torono-tepui, on rainforest slope, 515-750 m alt, Steyermark d Wurdack 226, Jan 24, 1955, (NY). Habitat, Hosts and Economic Importance. It grows on wood and on buried roots. No host is known from Venezuela or from any place else and the rot produced by this fungus is also unknown.

Discussion:

Figs. 11-12.

Polystictus hamatus (Romell) Sacc, Syll. Fung. 16: 255. 1902.

Type. Holotype, Malme 530, Feb. 19, 1894, at S.

Type Locality. Santa Ana de Chapada, Mato Grosso, Brazil.

Basionym. Pelloporus hamatus Romell, 1901.

Discussion. The Venezuelan collection was compared with a merotype of Pelloporus hamatus Romell at BPI. The type is shghtly smaller but shows the same macroscopic aspect of the Venezuelan collection and in the lower part of the context and at the dissepiments in both striking, dark brown setal skeletal hyphae are present whose uncinate to straight tips sometimes project beyond the basidial layer. Romell (1901: 26) had already called attention to the presence of "setae," 6-12 µ diam, up to 300 µ in the type. These setae are not true hymenial setae but are setal skeletal hyphae originating deep in the dissepiments or even in the lower part of the context; they sometimes project into the hymenium. We believe that these hyphae are homologous to the setal skeletal hyphae found in Phellinus pachyphloeus (Pat.) Pat. and that the lower part of the context and the dissepiments for this reason show an incipient dimitism due to the evident predominance of generative hyphae and the presence of a few setal skeletal hyphae. The study of P. pachyphloeus and its allies proved that setal skeletal hyphae and hymenial setae are completely independent structures; the presence of one does not imply necessarily the presence of the other; they m a y appear together or alone.

As the true position of Pelloporus hamatus Romell is still questionable we refer to it under its basionym. According to Donk (1960: 250), the genus Pelloporus Quel, should be typified by Polyporus perennis (L.) ex Fr. and thus would be a typonym of Coltricia S. F. Gray. There is still lack of some important data on P- hamatus, for instance, the color of the basidiospores; apparently no one has examined a fresh collection of it. The Venezuelan collection is sterile; the type shows yellow to yellowish-brown basidiospores but there is a question as to whether or not the basidiospores were hyaline when fresh.