Marasmius caesius Murrill, Bull. Torrey Bot.

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 : 128

Marasmius caesius Murrill, Bull. Torrey Bot. Club 67: 148. 1940. Fig. 10h–k

Holotype:— UNITED STATES. Florida: Gainesville , on oak sticks in high hammock, 28 May 1938, leg. Murrill ( FLAS F-18263!).

The holotype specimen consists of approx. 10 basidiomes in good condition. Description of dried holotype: Pileus convex, pruinose, smooth, cream-tan. Lamellae adnate, subdistant to distant, narrow to moderately broad, pallid. Stipe pruinose to pubescent, pallid, cream-tan, non-insititious, arising from a ring of radiating cream-colored mycelium. Lignicolous on oak sticks. Basidiospores 8.4–10.8 × 7.2–9.8 μm (x m = 9.6 × 8.3 μm, n = 20), tetrahedral, hyaline, inamyloid, thin-walled. Basidia 24–32 × 6.5–8 μm, 4-sterigmate, clavate, clamped. Basidioles clavate. Pleurocystidia absent. Cheilocystidia numerous, 20–40 × 4–6.5 μm, irregularly cylindrical, diverticulate overall or only on central axis, with a smooth, often subcapitate apex, sometimes lobed; diverticula 1.5–6.5 × 1–3.2 μm. Pileipellis a well-developed Rameales -structure; hyphae strongly diverticulate, 4–6.5 μm diam., hyaline, inamyloid, clamped, noninflated, non-gelatinous; terminal cells strongly diverticulate and often capped with a smooth bulbous capitulum; diverticula 1.5–5 × 1–2.5 μm, rod-like, obtuse, hyaline. Pileus margin with erect pileocystidia with bulbous apices like the cheilocystidia. Pileus trama of interwoven, cylindrical hyphae 2.5–6.5 μm diam., hyaline, inamyloid, non-gelatinous to weakly gelatinous. Stipitipellis a Rameales -structure like the pileipellis. Stipe cortical hyphae and medullary hyphae similar, subparallel, 2–5.5 μm diam., hyaline to pale yellow, inamyloid, smooth, with walls <0.5 μm thick. Clamp connections present.

Status: Marasmius caesius represents a synonym of Tetrapyrgos nigripes .

Figures

FIGURE 10. Anatomical features for: Campanella tenuitunicata (Singer T1750—Holotype a–c). a. Basidiospores. b. Basidium. c. Hymenial cystidia. Gymnopus floridanus (F-18290—Holotype d–g). d. Basidioles. e. Cheilocystidia. f. Pileipellis terminal cells. g. Caulocystidia. Marasmius caesius (F-18263—Holotype h–k). h. Basidiospores. i. Basidium and basidiole. j. Cheilocystidia. k. Pileipellis terminal cells. Scale bar = 10 μm. Illustrated by D.E. Desjardin.