Tetrapyrgos longicystidiata A.H. Honan, Desjardin & T.J. Baroni, 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 : 108-110

Tetrapyrgos longicystidiata A.H. Honan, Desjardin & T.J. Baroni spec. nov. Fig. 2a–f

Mycobank: MB 813638

Etymology: Refers to the comparatively long cheilocystidia.

Holotype:— PUERTO RICO. Sierra de Cayey, 23 June 1996, leg. TJ Baroni 7935 ( CORT!).

Diagnosis: Pileus 10–19 mm diam., convex with incurved margin when young, becoming broadly convex to plano-convex with scalloped to undulate, straight to upturned, striate to striatulate margin in age; surface dull, dry, minutely pruinose overall; disc grey (6E2) and margin white when young, disc remaining grey or becoming grey-brown (6E3), with dingy dark grey (7F2) or olivaceous grey (4E3) spotting and a white margin in age; always with a grey to olivaceous grey disc and splotches and a white margin. Context 1 mm thick, white, unchanging. Lamellae adnate to arcuate, subdistant with 2 series of lamellulae, not or slightly intervenose, white with olive grey spots in age. Stipe 25–43 × 1–2 mm, stout, central, terete or with flared apex and gradually narrowed downward, tough, pliant, twistedfibrous, hollow, subinsititious from a flattened circular pad of grey appressed mycelium; surface dull, dry, appressed-fibrillose with a granular white covering; apex pure white; base becoming dark charcoal grey to black with a hint of bluish black. Odor and taste not distinctive.

Basidiospores 7.2–12.8 × 6.0–9.6 μm [x mr = 9–10 × 7.9–8.9 μm, x mm = 9.5 ± 0.4 × 8.1 ± 0.6 μm, Q = 1–1.5, Q mr = 1.1–1.2, Q mm = 1.2 ± 0.04, n = 20, s = 5], tetrahedral, hyaline, inamyloid, thin-walled. Basidia clavate, 4-spored, hyaline, inamyloid, thin-walled, clamped. Basidioles 25.6–28.6 × 3.6–8.0 μm, clavate to fusoid. Pleurocystidia absent. Cheilocystidia 26.4–63.2 × 3.2–4.8 (–7.2) μm; apex bulbous and often branching, occasionally diverticulate, hyaline, inamyloid, thin-walled; central axis sparsely to densely diverticulate; diverticula 0.8–7.2 × 0.8–3.2 μm, cylindrical or knob-like, occasionally branched or acute. Pileipellis a Rameales -structure of loosely interwoven diverticulate hyphae 2.4–8.8 μm diam, with a nearly trichodermium layer of suberect to erect terminal cells; terminal cells 20–52 × 3.2–4.8 (–7.2) μm, with apex bulbous and smooth, often branching, elsewhere diverticulate, hyaline, inamyloid, thin-walled; diverticula 0.8–7.2 × 0.8–3.2 μm, cylindrical or knob-like, occasionally branched, rarely acute. Lamellar trama interwoven, hyphae cylindrical, smooth. Stipe tissue monomitic; hyphae 2.8–6.4 μm diam., parallel, cylindrical, yellowish brown, inamyloid, thin-walled. Caulocystidia 42–63 × 5–7 μm, mostly with a branching bulbous apex, diverticulate, hyaline, inamyloid, thin-walled; diverticula 0.8–6.4 × 0.8–3.6 μm, cylindrical or knob-like, simple or branched. Clamp connections present.

Habitat and known distribution: Gregarious on decaying leaves and sticks of Quercus spp . (in Costa Rica), and undetermined dicotyledonous wood and occasionally leaves. Argentina, Bolivia, Brazil, British Virgin Islands, Costa Rica, Puerto Rico.

Material examined:— ARGENTINA. Tucumán, Instituto Lillo , 1 March 1962, E Horak 62-092 ( ZT) ; Misiones Prov.: Iguazu , 3 March 1980, E Horak 207 ( ZT) ; same location, 4 March 1980, E Horak 1871 ( ZT). BOLIVIA. Dept. Beni, José Ballivian Prov.: along banks of Río Beni S of Rurrenabaque, between Rurrenabaque and junction of Río Tuichi , 31 March 1990, RE Halling 6376 ( NY). BRAZIL. São Paulo State: Municipal Iporanga Parque Estadual Turistico Do Alto Riberia ( PETAR), conservation area at Bairro da Serra , 8 March 2005, DE Desjardin 7817 ( SP, SFSU). BRITISH VIRGIN ISLANDS. Guana Island : upper 1/3 Quail Dove Ghut, 18 October 1997, DJ Lodge 32

(SFSU); St. John Island: Reef Bay Trail, 17 November 1996, S Cantrell & DJ Lodge 9632 ( CFMR (StJ306)). COSTA RICA. Guanacaste Prov.: Santa Rosa N. P., 21 May 1996, RE Halling 7542 ( NY), same location, 14 June 2003, E Horak 10395 ( ZT) ; same location, 18 June 2003, RE Halling 8396 ( NY) ; Guanacaste Prov.: P. N. Rincon de la Vieja, Biol. Station Cacao, 17 June 2003, E Horak 12385 ( ZT). PUERTO RICO. El Yunque National Forest , El Verde Field Station , 19 June 1996, TJ Baroni 7902 ( CORT) ; same location, 19 June 2006, E Horak 5661 ( ZT) ; Sabana, ridge above chicken farm, TJ Baroni and B Ortiz 8305 ( CORT) ; Sierra de Cayey, 23 June 1996, TJ Baroni 7935 ( CORT, holotype) .

Commentary: Tetrapyrgos longicystidiata is characterized by a pruinose pileus with olivaceous grey disc and white margin, diverticulate cystidial elements with bulbous apices, and a black or blue-black stipe covered with a white pruina and arising from a dark basal disc. This new species resembles T. nigripes in morphology and substrate, and overlaps in distribution. Tetrapyrgos longicystidiata differs from T. nigripes in having longer cheilocystidia, with many over 50 μm long, and in having a pileus with a consistently grey to olivaceous grey disc. Analyses of ITS sequence data support the distinction of this taxon as a new species. The taxon reported from Trinidad by Dennis (1951) as Marasmius nigripes probably represents T. longicystidiata .

Figures

FIGURE 2. Macroscopic and anatomical features for Tetrapyrgos longicystidiata (DED 7817). a. Basidiomes. b. Basidiospores. c. Basidium and basidioles. d. Cheilocystidia. e. Pileipellis terminal cells. f. Caulocystidia. Scale bars: a = 10 mm, b–f = 10 μm. Illustrated by D.E. Desjardin.