Name: Trichaptum sector
Author: (Ehrenb.) Kreisel
Citation: Monografias Ciencias Universidad de Habana 16: 84 (1971) [MB#324872]
Deprecated Synonyms: Boletus sector Ehrenb., Polyporus sector (Ehrenb.) Fr., Polystictus sector (Ehrenb.) Sacc., Microporus sector (Ehrenb.) Kuntze, Coriolus sector (Ehrenb.) Pat., Polyporus floridanus Berk., Polyporus ludens Speg., Polystictus nebularis Cooke, Polystictus fulvicolor Speg., Polystictus sordidissimus Speg.
Pileus sessile, dimidiate to flabelliform, thin, relatively flexible when dry; upper surface tomentose to velutinate, often rough to cristate toward base, zonate with alternating light and dark bands of brownish pink; adhymenial surface light greyish red brown to almost black, pores angular, thin-walled, dentate, 3-6/mm, 1.5 mm deep.
Spores 4.5-5 × 2-2.5 µm, subcylindrical to cylindrical, thin-walled, hyaline, IKI-, acyanophilous, with an inconspicuous hilar appendage.
In section the context is of dense strands of brown skeletal hyphae held together by branching or twisting narrower hyaline hyphae; skeletals turn downward forming the pore walls held together as in the context; tubes lined with a hymenium of basidia and hyaline, slightly thick-walled incrusted cystidioles, usually with acute apices, on occasion skeletal hyphae protrude into the base of the hymenium with their apices rounded and slightly swollen, tomentum of mixed skeletal and generative hyphae; cuticle of a ± compact hyphal layer.
Generative hyphae hyaline or faintly pigmented, clamped, thin-walled, ca. 2-3 µm in diam with cells up to at least 130 µm in length, others with capillary or no lumen, ca. 4 µm in diam, both types branch frequently, thick-walled ones sometimes with short branching laterals, often from site of clamp-connection; skeletals hyaline to light brown, generally with lumina completely occluded, 4-7 µm in diam, some pigmented ones form hyaline twisting extensions ca. 3 µm in diam with one or more short spurs.
The twisting extensions from the skeletals and the branching solid lateral extensions from the generative hyphae perform the “binding” function. No truly binding hyphae such as those seen in some Trametes Fr. were observed. We are interpreting the structure of T. sector as dimitic with skeletal and generative hyphae.
This fungus is found throughout Mexico and Central America and occurs frequently in the bottomland hardwood forests of Louisiana, U.S.A. Gilbertson and Ryvarden (1987) report it as a characteristic element of such regions. With a spore print, from which to take measurements, the fungus can be identified by its usually darkened pore surface and its thin flexible, tomentose pileus with its typical colours. It is found in our region on dead hardwoods, where it causes a white rot.