Tetrapyrgos parvispora A.H. Honan & Desjardin, 2015

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 : 113-114

Tetrapyrgos parvispora A.H. Honan & Desjardin spec. nov. Fig. 5a–f

Mycobank: MB 813639

Etymology: Refers to the small spores.

Holotype:— THAILAND. Chiang Mai Province: Mae Sae Village, Highway 1095 at 50 km marker, 26 June 2005, AH Honan 130 ( CMU!).

Diagnosis: Pileus 2–19 mm diam., hemispherical to convex with straight and sometimes crenate or rivulose margin when young, becoming convex to plano-convex and slightly depressed with straight or occasionally reflexed margin in age; surface dull, dry, subglabrous or covered in white pruinae, not hygrophanous; disc dark greyish brown (6–7E– F3) to greyish brown (7D–E3) with a paler margin when young, becoming greyish white to off-white or brownish grey (6C2) overall through development, with pellucid brownish grey (6C2) striations developing in age. Context in pileus 0.5 mm thick, white. Lamellae adnate or adnate with a decurrent tooth, close to distant, with 2–3 series of lamellulae, shallowly intervenose and anastomosing, up to 2 mm broad, white, staining greyish blue. Stipe 5–34 × 1–1.5 mm, central, terete, cylindrical or with slightly flared apex and gradually narrowed downward, subinsititious from a flattened circular disc of bluish black mycelium, white-pruinose overall; apex white, base becoming dark grey to black with a hint of bluish black. Odor and taste not distinctive.

Basidiospores (4.8–) 5.6–8.8 (–9.6) × 4.8–8 μm [x mr = 6.8–7.8 × 5.8–6.2 μm, x mm = 7.3 ± 0.54 × 6.5 ± 0.18 μm, Q = 1.0–1.8, Q mr = 1.1–1.4, Q mm = 1.2 ± 0.12, n = 20, s = 4], tetrahedral, hyaline, inamyloid, thin-walled. Basidia 21–27 × 4–7 μm, clavate, 4-spored, hyaline, inamyloid, thin walled, clamped. Basidioles 20–28 × 3.2–7.2 μm, clavate to fusoid. Pleurocystidia absent. Cheilocystidia 15–44 × 3–6 μm; apex usually smooth and bulbous, often branched; central axis diverticulate, hyaline, inamyloid, thin-walled; diverticula 0.8–5.6 × 0.8–4 μm, cylindrical or knob-like, occasionally branched or acute. Pileipellis a Rameales -structure of loosely interwoven diverticulate hyphae 3–8 μm diam., with nearly a trichodermium layer of erect terminal cells; terminal cells 10.5–31 × 3–5 μm, with apex smooth and bulbous, often branched, elsewhere diverticulate, hyaline or with yellowish brown pigments washing out in KOH, inamyloid, thin-walled; diverticula 0.8–4.8 × 0.8–3 μm, cylindrical or knob-like, occasionally branched, rarely acute. Lamellar trama interwoven; hyphae cylindrical, smooth. Stipe tissue monomitic; hyphae 3.2–8.8 μm diam., parallel, cylindrical, yellowish brown, inamyloid, thin-walled. Caulocystidia 24–36 × 3.2–6.4 μm, mostly with a branched, smooth, bulbous apex, elsewhere diverticulate, hyaline, inamyloid, thin-walled; diverticula 0.8–7.2 × 0.8–6.5 μm, cylindrical or knob-like, occasionally branched or acute. Clamp connections present.

Habitat and known distribution: Solitary on decaying undetermined dicotyledonous leaves and twigs. Thailand.

Material examined:— THAILAND. Chiang Mai Province: Papae Village, Highway 1095 at 22 km marker, N19˚07.57', E98˚45.647', 2 July 2003, DE Desjardin 7603 ( SFSU) ; same location, 23 June 2004, AH Honan 25 and AH Honan 26 ( SFSU) ; same location, 5 July 2004, AH Honan 66 ( SFSU) ; same location, 21 June 2005, AH Honan 122 ( SFSU) ; Chiang Mai Province: Mae Sae Village, Highway 1095 at 50 km marker, 26 June 2005, AH Honan 130 ( CMU, holotype; SFSU, isotype) .

Commentary: Tetrapyrgos parvispora appears to be endemic to a small area in Northern Thailand. This may be an artifact of limited collecting and future collections may prove that T. parvispora has a wider distribution than currently recognized. The species differs from other centrally stipitate Tetrapyrgos by having smaller basidiospores, averaging 7.3 × 6.5 μm. Morphological analyses and ITS sequence data (95% PP) support T. parvispora as a distinct species.

Figures

FIGURE 5. Macroscopic and anatomical features for Tetrapyrgos parvispora (AHH 130—Holotype). a. Basidiomes. b. Basidiospores. c. Basidia and basidioles. d. Cheilocystidia. e. Pileipellis terminal cells. f. Caulocystidia. Scale bars: a = 10 mm, b–f = 10 μm. Illustrated by D.E. Desjardin.