Setigeroclavula ascendens R.H. Petersen 1988
Details
Biostatus
Nomenclature
Classification
Associations
Descriptions
Setigeroclavula ascendens R.H. Petersen 1988
Fruit bodies (Fig. 133) up to 3 mm high, up to 1 mm broad, broadly clavate from an equal stipe, consistently bent to one side, arising from minute white basal tomenta, white; flesh solid.
Stipe surface hyphae 3-13 gm diam., hyaline, inflated, thick-walled (wall up to 0.5 gm thick), producing caulocystidia; crystalline material copious on stipe surface. Caulocystidia (Fig. 134) up to 85 x 8 pm, narrowly lanceolate, hyaline, thick-walled below (wall up to 0.7 gm thick), thin-walled apically, tapering gradually upward, rooting somewhat, apically covered with minutely fibrillose material. Tramal hyphae 2-5 gm diam., hyaline, adherent, thin-walled, without clamp connections. Subhymenium rudimentary, crushed. Hymenium thickening; basidia (Fig. 135) about 40 x 8 gm, cylindrical, crumpled but persistent after spore discharge; contents homogeneous; sterigmata 2, up to 7 gm long, divergent, straight. Hymenial cystidia (Fig. 136) up to 200 x 15 gm, lanceolate, hyaline, brittle, thick-walled (wall usually obscuring cell lumen) throughout lower 7/8, thin-walled at apex, covered here and there by amorphous hyaline material, and with apex covered with minutely fibrillose material.
Spores (Fig. 137) 9-11.5 x 7.6-9.4 gm (E =1.18-1.38; E'° = 1.24; L, = 10.08 gm), broadly ellipsoid, smooth, hyaline, thin-walled; contents homogeneous; hilar appendix papillate.
Fruit bodies seem to arise ageotropically, bending upward as they mature. Thus, they must qualify as clavarioid, for the hymenium is amphigenous. At the same time, only Dimorphocystis resembles this collection, but differs in the following ways: (i) Dimorphocystis taxa produce two distinctly different cystidial types, only one of which resembles the cystidia of this collection; (ii) hyphal construction in Dimorphocystis in dimitic, with skeletal hyphae, whereas in the collection below if is monomitic; and (iii) the spores of all three taxa of Dimorphocystis are of significantly higher Em value than those of the collection cited below.
For all these reasons, I feel sure that this single collection represents a new taxon, but at what rank? Given the characters of Dimorphocystis listed above; this collection surely represents a new genus. But I am reluctant to propose a new genus based on one collection of perhaps one half-dozen fruit bodies.
Concommitantly, if one were to compare this collection to Corner's circumscription of Dimorphocystis subcapitatus, the following similarities would be noted: (i) rather similar lanceolate hymenial