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Page number:1171 
Description type:Non-original description 
Description:Trechispora regularis (Murrill) Liberta (Figs 15-16, 28-29, 39 A-F) Can. J. Bot. 51:1878 (1973)
Poria regularis Murrill, Mycologia 12:87 (1920). Holotype: Jamaica. Leg. Murrill 703 (NY)
For a list of suggested synonyms, see Liberta (1973) Basidiomata resupinate, effused, easily separable from the substratum, soft and fragile. Margin abrupt, thinning out or consisting of radiating hyphal mats with cord-like structures. Hymenophore poroid, pores varying from very shallow to 2 mm deep, also varying in shape from rounded and 3-4/mm to angular and more or less reticulate and much wider, on slooping substrate growing sublamellate, easily separable from the subiculum, white to light ochraceous. Hyphal system monomitic, all septa with clamps. Cords abundant in the subiculum and in the substrate, with thin-walled, straight, 2-5 µm wide hyphae lacking incrustations, also thick-walled, 3-5 µm wide, heavily incrusted hyphae, often as sections interspaced in thin-walled hyphae, ampullate septa abundant, up to 9 µm wide. Subiculum thin to thick, byssoid, with randomly growing, thin-walled, 2-5 µm wide hyphae and thick-walled, heavily incrusted segments or hyphal ends up to 75 µm long. Dissepiments with moderately short-celled, thin-walled hyphae, growing parallel and being 3-5 µm wide, cystidia-like, thick-walled, incrusted hyphal ends abundant. Subhymenium very thin or absent, usually only one to a few cells thick, with short-celled, much branched, rounded or irregular, 2-5(-10) µm wide hyphae, branching at right angles from tramal hyphae. Basidia cylindrical to doliform, sometimes with a slight median constriction, frequently seen as pleurobasidia when borne close to the end of a tramal hypha, (7.5-)10-13(-15) x (4-)5-6 µm, with four, slender, curved, up to 3.5 µm long sterigmata. Spores densely aculeate, subglobose, slightly flattened on the adaxial side 4-5.5 x 3.5-5 µm including ornamentation, aculei 0.5-1.0 µm long. Crystals on cystidia-like hyphae and on thick-walled segments arranged as sheaths formed by jagged ridges along the hyphae. Crystals on other hyphae as flattened bipyramides.
T, regularis grows on a variety of woody substrates and, in most cases, the wood is in a strongly decayed condition. The distribution is tropical- subtropical, extending into nemoral areas in eastern North America.
T. regularis has a wide distribution and shows considerable morphological variation in the basidiome as well as in hyphal structure, distribution of crystals, and spore ornamentation. This may indicate that the collections studied is not an homogenous assemblage and that further collecting will give sufficient information for splitting them in several taxa.
The incrusted hyphal ends usually has been interpreted as cystidia (Lowe, 1966; Liberta, 1973; Gilbertson & Ryvarden, 1987). The incrusted parts differ markedly from other hyphae because of their thickened walls but since they occur both terminally and intercalary on the hyphae they should not be termed cystidia. These specialized hyphal segments are unique in Trechispora and should, together with the poroid hymenophore, make T. regularis an easily identified species.
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