Monographs Details: Hexagona capillacea Pat. & Gaillard
Authority: Fidalgo, Oswaldo & Fidalgo, Maria E. 1968. Polyporaceae from Venezuela. I. Mem. New York Bot. Gard. 17 (2): 1--34.
Description:Species Description - MACROSCOPIC CHARACTERS. Fruiting body annual, solitary, always sessile, attached to the substrate by a small pilear portion; pileus dimidiate, convex, 5-10 X 3-4.5 X 0.3-0.7(-1.2) cm, coriaceus; pilear surface chestnut-brown to ferrugineus-brown, IV1P-15C11 (Cocoa Brown), MP-8L8 (Brazil Brown) to MP-8J8 (Java Brown), strigose, densely covered by dark brown, branched, prostrate hairs; margin thin, acute and undulate, concolorous with the pilear surface. Context coriaceous, dark brown, MP-15A12 (Burnt Umber), subhomogeneous,
very thin, about 0.5 mm thick, permanently darkening in KOH solution. Hymenial surface dark brown, MP-SAll (Wren) to MP-15A12 (Burnt Umber), poroid, with angular, hexagonal pores, radially elongated, with (2-) 3-1.5 pores per cm near the center, smaller at the margin, 4.5-6(-8) per cm; tubes dark brown, MP-15A12 (Burnt Umber), 0.1-0.6(-0.9) cm long; dissepiments 170-450 µ thick. MICROSCOPIC CHARACTERS. Pilear surface with a fasciculated trichoderm, with very long hairs, forked or branched, soft-prostrate, 1000-4000 p long, 160-580 µ diam, each hair being formed by a tuft of skeletal hyphae with anticlinal orientation, coarsely bound by thin generative and binding hyphae, covering the pilear surface, at the insertions of the hair-tufts a thin, dark layer, a cutis, formed by the agglutination of the outer hyphae of the context, showing a periclinal orientation. Context and dissepiments formed by a trimitic hyphal system. Generative hyphae hyaline, thin-walled, septate, with clamps, branched, nonamyloid, 1.5-2.5(-3) µ diam, very difficult to observe in the mature fruiting body, mostly found collapsed and in rather small numbers; skeletal hyphae yellowish-brown to brown, slightly thickened to strongly thick-walled, but always with a distinct lumen, rarely subsolid, not septate, but sometimes with thin and curved, simple septa near the apical part, unbranched, 2.5-5 (-7.5) µ diam, abundant; binding hyphae hyaline to yellowish, thickened to subsolid, much branched, not septate, (1-) 1.5-2.5(-7.5) µ diam; context when viewed in section presenting a slight differentiation into two layers, a fibrose upper layer formed mostly by skeletal hyphae showing a periclinal orientation and a lower layer, more compact, formed by skeletal and few number of binding, neither type showing a definite orientation. Dissepiments formed by skeletal and binding hyphae, equally abundant, much interwoven and not showing a definite orientation. Generative hyphae rather inconspicuous in the context and dissepiments of the mature fruiting body. Hymenium: setae, cystidia, cystidioles and cystidioid hyphae not observed; pseudo-setae brown, very thick-walled to subsolid, usually with a refringent guttule in the lumen, variously shaped, fusiform to ventricose, sometimes forked, also very variable in size, (14.5-) 17-37.5(-50) x (3-)4.5-7(-9) µ, sometimes with a deposit at the apex, always originating from a clamp in the subhymenium; most pseudosetae with collapsed or fragmented basal generative hyphae, projecting into the lumen of the tube and overlapping the basidia throughout the hymenium, but more frequent near the edge of the tubes, appearing almost grouped; hyphal pegs yellowish-brown, conic, 35-100 X 30-55 µ; basidia hyaline, clavate. tetrasterigmate, (11-)13-15.5 X (4-)5-7 µ, mostly collapsed; collapsed; basidiospores hyaline, cylindric, smooth, nonamjdoid, 9.5-10.5 X 3.2-3.5 µ.
Distribution and Ecology - Habitat, Hosts and Economic Importance. Hexagona capillacea so far is known to occur on old trunks and dead branches. There is one report listing it as growing on dead branches of "merecure" which is Aloquilea macrocarpa Pittier by Patouillard and Heim (1928: 269), from Venezuela. The associated rot is unknown. Specimens examined. South America. BRAZIL. Amazonas: Amazon Valley, Weir, 1923 (BPI, as H. hirta). Bahia: Saude, Torrend (URM 9732); locality not indicated, Torrend, (Lloyd 9932 at BPI); locality not indicated, Torrend, Jul 1924 (BPI). Mato Grosso: Rio Ouro Preto, Weir, Sep 9-17, 1923 (BPI, as H. hirta). COLOMBIA. Bolivar: near Los Pueblos, Land of Lobos, Lorenz 3165, Feb 1941 (BPI). VENEZUELA. Amazonas: San Fernando de Atabapo, Gaillard 204, Sep 1887 (Exs. herb. Patouillard at F H 2681, holotype of H. capillacea; merotype in Bresadola herbarium at BPI) ; Rio Ventuari, Cerro Moriche, Riverine forest, Maguire, Cowan & Wurdack 31044, Jan 22, 1951 (NY; SP 70519). Geographical Distribution. Hexagona capillacea appears to be a rare species so far known only from three South American countries (Brazil, Colombia and Venezuela). It was reported twice from Venezuela, by Patouillard and Gaillard (1888: 36) and by Patouillard and Heim (1928: 269), respectively, from Amazonas Territory and from Apure State. Since then it was found a few times by Torrend (1935: 110; 1940: 326) in Bahia State, Brazil, in the localities of Tamandua forest, Itaparica I., and Conquista district. One of these collections was sent to Lloyd (1925a: 1334) and is now at BPI. Two collections made by J. R. Weir are also at BPI, lalielled as H. hirta; they both represent new records of H. capillacea for Amazonas and Mato Grosso States, Brazil. Another collection at NY by B. Maguire and collaborators was found very near the type locality in Venezuela. The collection from Colombia at BPI is apparently the first record from that country. In the general herbarium at FH is a collection from Nicaragua determined as H . capillacea but it is a tvpical specimen of Coriolus pinsitus (Fr ) Pat.
Figs. 14, 15, 48-54.
Scenidium capillaceum (Pat. & Gaillard) Kuntze, Rev. Gen. Pl. 3(3): 516. 1898.
Type. Holotype collected by Gaillard, deposited in Patouillard herbarium at Farlow Herb. (FH) ; merotype at BPI.
Type Locality. S. Fernando de Atabapo, Amazonas Territory, Venezuela.
Basionym. Hexagona capillacea Pat. & Gaillard, 1888.
Illustrations. Lloyd, Mycol. Writ. 3 (Syn. Hexagona): fig. 281. 1910; Mycol. Writ. 7: fig. 3070. 1925 (as H. capillacea).
Discussion. The closest relatives to Hexagona capillacea appear to be H. apiaria and H. hirta; the three have the same macroscopic aspect, with slight variation in the size of pores. H. capillacea, however, can be separated easily from the others by its hymenium having an unique characteristic, the brown, thick-walled, seta-hke bodies, called pseudosetae in order to differentiate them from the common setae found in Phellinus, Inonotus, Hymenochaete, Clavariachaete and Hydnochaete, etc., which originate at a simple septum and usually have a definite shape and constant size. The pseudosetae of the hymenium of H. capillacea originate at the level of the subhymenium as true cystidia are formed, but in other aspects, such as shape, color and reaction to the KOH solution, they seem to be setae. Such an unusual characteristic for a species of Hexagona had already been noticed by Bresadola; he annotated one merotype (BPI) of this species: "Setula fulva, 20-24 x 6-9."
Basidiospores are rather difficult to find in the herbarium specimens. Of all the specimens examined only a Colombian collection (Lorenz 3165, BPI) was found with a fertile hymenium; in some other collections spores showing the same shape and dimensions of the basidiospores observed in the Colombian collection were seen scattered among the hairs of the pilear surface.
Torrend (1935: 110) considered Hexagona capillacea as very close to H. wildemani Bres. from the Congo. I think the similarities between these species are rather superficial and are limited to the strigose aspect furnished by the fasciculated trichoderm of the pilear surface. H. wildemani is not here considered as belonging to genus Hexagona emend.