Public Description of Marasmius tubulatus Petch

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Name: Marasmius tubulatus Petch
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Description status: Unreviewed

Taxonomic Classification:

Domain: Eukarya
Kingdom: Fungi
Phylum: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Marasmiaceae

General Description:

Marasmius tubulatus is charac- terized by a light brown or pale yellowish brown pileus with a dark central spot, distant lamellae (10-13) that are non-marginate or have light brown edges, relatively small basidiospores in the range 8-10 × 3-4.5 μm with mean of 9.3 × 4 μm, broad, light brown Rotalis-type broom cells on the pileipellis and lamellar edge, and by growth on dicotyle- donous leaves. The material from Malaysia differs only subtly from the protologue (Petch, 1947) and redescription (Pegler, 1986) of Sri Lanka specimens, in forming slightly larger pilei (up to 12 mm diam) that are more evenly pigmented and lack a distinct white margin. A tetrapolar (bifactorial) mating system was reported for M. tubulatus by Tan et al. (2007) based on Malaysian material.

Diagnostic Description:

Pileus 4-12 mm diam, broadly conical and truncate to broadly convex or convex with a shallowly depressed disc, striate to sulcate; surface dry, dull, minutely pruinose; grayish yellow (4B4-5) to grayish orange (5B3-5), yellowish brown (5D5), light brown (6D5-6) or brown (6E6-5) with a central black dot. Lamellae adnate to a collarium, distant (10-13), yellowish white, non-marginate or more commonly with light brown marginate edges. Stipe 10-32 × 0.5 mm, central, terete, equal, cylindrical, dry, dull, glabrous, insititious, yellowish white to light brown at apex, dark brown to dark brown at base.

Basidiospores (7-) 8-10.5 × 3-4.5 (-5) μm, [xmr = 8.7-10.3 × 3.9-4.1 μm, xmm = 9.3 ± 0.6 × 4 ± 0.2 μm, Q = 1.7-3.3, Qmr = 2.2-2.7, Qmm = 2.4 ± 0.1, n = 23 spores per 9 collections], ellipsoid, smooth, hyaline, inamyloid. Basidia 21-27 × 6-7 μm, 2-spored and 4-spored. Basidioles 20-28 × 5-8 μm, fusoid to clavate. Cheilocystidia abundant, composed of Rotalis- type broom cells; main body 12-27 × 7-18 (-22) μm, subclavate to clavate or subglobose, hyaline, inamyloid, thin-walled or apically thick-walled; divergent setulae 1-3 × 0.5-1 μm, abundant over upper half of cell, cylindrical to conical, subacute to obtuse, light yellowish brown to light brown, weakly dextrinoid. Pleurocystidia absent. Pileipellis mottled, composed of a hymeniform layer of Rotalis- type broom cells; main body 10-35 (-41) × (7-)10-26 μm, cylindrical to clavate, subclavate, turbinate or subglobose, rarely lobed, hyaline to light yellow, inamyloid, thin-walled or apically thick-walled; divergent setulae 1-4 × 0.5-1 μm, abundant over upper half of cell, cylindrical to conical, subacute to obtuse, brownish yellow to brown, inamyloid, thin- walled. Pileus trama interwoven; hyphae 3-6 μm diam, hyaline, inamyloid to weakly dex- trinoid, thin-walled, non-gelatinous. Lamellar trama regular to subparallel; hyphae 4-8 μm diam, cylindrical, hyaline, dextrinoid, thin- walled, non-gelatinous. Stipe tissue monomitic; cortical hyphae 5-10 μm diam, parallel, cylindrical, smooth, yellowish brown to brown, weakly dextrinoid, thick-walled (up to 1 μm), non-gelatinous; medullary hyphae 4-8 μm diam, parallel, cylindrical, smooth, hyaline, inamy- loid, thin-walled, non-gelatinous. Caulocystidia absent. Clamp connections present.

Habit, habitat and known distribution: gregarious on leaves of undetermined
dicotyledonous trees. Malaysia (Johore), Sri Lanka.

Description author: Excited delirium [EXD]▼ (Request Authorship Credit)