Tetrapyrgos reducta (Singer) Horak, Sydowia

Honan, Amy H., Desjardin, Dennis E., Perry, Brian A., Horak, Egon & Baroni, Timothy J., 2015, Towards a better understanding of Tetrapyrgos (Basidiomycota, Agaricales): new species, type studies, and phylogenetic inferences, Phytotaxa 231 (2), pp. 101-132 : 114-115

Tetrapyrgos reducta (Singer) Horak, Sydowia 39: 102. 1987 [1986]. Fig. 4d–f

Basionym: Marasmiellus reductus Singer, Beih. Nova Hedwigia 44: 331. 1973.

Synonym: Pterospora reducta (Singer) E. Horak, Sydowia 36: 134. 1983.

Holotype:— BOLIVIA. Depto. La Paz, Prov. Nor-Yungas: Carmen Pampa , 1900–2000 m elev., 19 February 1956, Singer B 1266 (F 1015901!).

The holotype specimen consists of approx. 5 intact basidiomes in good condition attached to fragmented leaves of a bromeliaceous host plant.

Description of dried holotype: Pileus convex, granulose, pallid. Lamellae distant, well-developed, not-intervenose but may be vein-like. Stipe lateral, tiny, white-pruinose, pallid, subinsititious to non-insititious.

Macromorphological data adapted from the protologue ( Singer, 1973): Pileus 2–5 mm diam., obtuse, convex and depressed at stipe insertion, rear portion with sinus or incision, smooth to slightly sulcate-folded or very slightly sulcate, covered in white pubescence that is denser towards the margin, white to sordid white, becoming buff in age. Lamellae subfree to adnate, distant to subdistant, narrow, rarely vein-like or completely absent, simple to forked, with rather obtuse edges, white, eventually cream. Stipe lateral through development, very short and relatively broad, solid, equal or unequal, covered in white tomentum, usually subinsititious from thin basal disc, base rarely blackish brown in age. Context white, thin. Odor none.

Micromorphological analysis of the holotype: Basidiospores 8–11.2 × 5.5–7 μm, tetrahedral, hyaline, inamyloid, thin-walled. Basidia 4-sterigmate, clavate. Basidioles clavate. Pleurocystidia absent. Cheilocystidia common, scattered along lamellar edges, tibiiform, sometimes lobed, with diverticulate central axis and capitate apex; capitulum 4.5–6 μm diam.; length unmeasurable, hyaline, thin-walled. Pileipellis a well-developed Rameales -structure with coarsely diverticulate hyphae, sometimes apically lobed and capitate, hyaline, inamyloid, non-gelatinous, non-incrusted. Pileus trama of loosely interwoven hyphae 1.5–3 μm diam. with interspersed hyphae up to 14 μm diam., embedded in a thin gelatinous matrix, hyaline, inamyloid. Caulocystidia common, similar to cheilocystidia. Clamp connections present.

Habitat and known distribution: Scattered on bromeliaceous leaves. Bolivia.

Material examined: Holotype.

Commentary: This species is known only from the type specimen collected in 1956. Due to age and poor quality of the material, DNA extraction was not attempted. Additional collections of this taxon are necessary to determine the phylogenetic placement in Tetrapyrgos . In our microscopic analyses we observed the spores to be distinctly tetrahedral, which differs from the original protologue that describes the spores as ellipsoid with bulges. Tetrapyrgos tropicalis R.H. Petersen & S.A. Gordon is similar, differing only in larger spores, virescent basidiomes and dicotyledonous substrate. This species is also similar to T. subdendrophora , which differs in having less diverticulate cheilocystidia and more strongly intervenose lamellae.

Figures

FIGURE 4. Anatomical features for: Tetrapyrgos olivaceonigra (Horak ZT2131—Holotype a–c). a. Basidiospores. b. Basidium and basidiole. c. Cheilocystidia. Tetrapyrgos reducta (Singer B1266—Holotype d–f). d. Basidiospores. e. Cheilocystidia.f. Pileipellis terminal cell. Tetrapyrgos tropicalis (Gordon 3461—Holotype g) g. Basidiospores. Scale bar = 10 μm. Illustrated by D.E. Desjardin.