Tetrapyrgos tropicalis R.H. Petersen & S.A. Gordon, Mycologia

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 : 119-120

Tetrapyrgos tropicalis R.H. Petersen & S.A. Gordon, Mycologia 86: 755. 1994 (1995). Fig. 4g

Holotype:— PUERTO RICO. Caribbean National Forest , El Junque, Big Tree trail, on hardwood stick, 4 December 1990, RH Petersen and SA Gordon 3461 ( TENN 52380 !).

The holotype specimen consists of approx. 10 basidiomes in fair condition loose in the packet. Description of dried holotype: Pileus plano-convex, sulcate, cream-colored. Lamellae adnexed, distant, broad, edges crystalline. Stipe lateral, very dark, pruinose, subinsititious. On woody debris. Basidiospores 9–11.2 × 8–10.2 μm, tetrahedral, hyaline, inamyloid, thin-walled. All other micromorphological data confirmed as identical to those presented in the protologue.

Macromorphological data adapted from the protologue ( Petersen & Gordon 1994): Pileus 4–7 mm, conchate to reniform, crenate to striate, translucent, white to off-white, staining grey to greenish or olivaceous grey in age. Lamellae adnexed, distant, broad, white, staining like the pileus. Stipe short, <1 mm thick, eccentric, strongly curved, noninsititious, arising from a small off-white basal pad of mycelium with hispid margin; surface black with paler furfuraceous vesture. Odor and taste not recorded.

Micromorphological data adapted from the protologue: Basidiospores 11.4–15.6 × 8.6–13.1 μm (Q = 1.11–1.57, Q m = 1.33, width m = 14.09 μm), tetrahedral, hyaline, inamyloid, thin-walled. Basidia 29–31 × 12.5–13.5 μm, broadly clavate, 4-spored, clamped. Pleurocystidia absent. Cheilocystidia abundant, subcylindrical with 1–2 bulbous apices, diverticulate (size not reported). Pileipellis a Rameales -structure of hyphae 2.5–3.5 μm diam., branched and coarsely diverticulate, arising from subpellis hyphae swollen up to 13 μm diam. Stipe tissue modified sarcodimitic, of two types of hyphae: 1) 8–13 μm diam, unclamped, hyaline, with walls up to 0.5 μm thick; and 2) 1.8–2.5 μm diam., clamped, hyaline to brown near vesture, with walls up to 0.5 μm thick. Caulocystidia similar to cheilocystidia, with subcapitate or multilobate apices, diverticulate (size not reported). Clamp connections present on some but not all hyphae.

Habitat and known distribution: Scattered on hardwood sticks. Puerto Rico.

Commentary: This species is similar to the eccentrically stipitate species T. reducta , T. olivaceonigra and T. subdendrophora . Tetrapyrgos tropicalis differs from T. reducta in forming broader basidiospores and growing on dicotyledonous substrates, and from T.olivaceonigra and T.subdendrophora in forming a less intervenose hymenophore. Permission for DNA extraction from the holotype specimen was not granted; consequently, the phylogenetic placement of this species remains uncertain. Our analysis of the holotype specimen revealed basidiospores slightly smaller than those reported in the protologue.

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.