Public Description of Marasmius Fr.

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Name: Marasmius Fr.
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Description status: Unreviewed

General Description:

Marasmius iras, described from specimens collected in Malaysia, is characterized by a yellowish brown pileus with dark brown disc, subdistant, yellowish white lamellae, a subvelutinous stipe, fusoid basidiospores, non-setulose caulocystidia, and an absence of pleurocystidia and Siccus-type broom cells on the stipe surface. The Thai specimens match quite closely the Malaysian type except for having slightly smaller basidiospores with mean 12.8 × 3.7 μm vs. 14.1 × 3.7 μm, and longer setulae of cheilocystidia (4-11μm vs 4-7 μm long). Marasmius iras is phenetically similar to M. xestocephalus (see above), but the latter species differs in forming pilei with yellow tones and apically forked, thicker-walled caulocystidia.

http://www.fungaldiversity.org/fdp/sfdp/FD37-5.pdf


Diagnostic Description:

Pileus 5-20 mm diam., convex when young, expanding to plano-convex with slightly depressed disc in age, striate to sulcate, pruinose, dull, dark yellowish brown (5F8-5E6) to dark brown (6E8). Context yellowish brown (5E8), thin. Lamellae adnexed to adnate, subdistant (12-17) with 3 series of lamellulae, narrow, cream brown to brownish orange (5C5) with brown edges, non-intervenose. Stipe 17- 43 × 0.5-1 mm, central, cylindrical, hollow, subvelutinous, non-insititious, apex yellowish
white (3A2), base reddish brown (8E7). Odor and taste not distinctive.

Basidiospores (11-)12-14(-15) × 3-4(-5) μm [xmr = 12.6-13.4 × 3.4-4.2, xmm = 12.8 ± 0.5 ×3.7±0.4μm,Qmr =3.0-3.7,Qmm =3.5±0.4, n = 25 spores, s = 3 specimens], fusiod, smooth, hyaline, inamyloid, thin-walled. Basidia not observed. Basidioles fusoid to clavate. Cheilocystidia common, of Siccus-type broom cells; main body (8-)13-21 × 5-7(-10) μm, cylindrical to clavate or irregular in outline, seldom branched, hyaline, inamyloid, thin- walled; apical setulae (2-)4-9(-11) × 1-1.5(-2) μm, cylindrical, obtuse to subacute, yellow to brown, thick-walled. Pleurocystidia absent. Pileipellis hymeniform, mottled to weakly mottled, composed of Siccus-type broom cells; main body 12-25 × 5-9 μm, cylindrical to clavate or turbinate, seldom branched, hyaline, inamyloid, thin-walled; apical setulae 3-8 × 1 μm, crowded, cylindrical to irregular in outline, obtuse to subacute, dark brown to black, thick- walled. Pileus trama interwoven, dextrinoid. Lamellar trama hyphae 3-8(-10) μm diam., interwoven, cylindrical, smooth, hyaline, dextrinoid, thin-walled, non-gelatinous. Stipiti- pellis hyphae 3-7(-10) μm diam., subparallel, cylindrical, yellow to brown, smooth, inamyloid to weakly dextrinoid, thick-walled (up to 1 μm), non-gelatinous. Stipe trama hyphae 4-10(-13) μm diam., parallel, cylin- drical, hyaline, smooth, dextrinoid, thin-walled, non-gelatinous. Caulocystidia numerous, 23-43 × 6-10 μm, cylindrical to clavate or irregular in outline, rarely lobed, hyaline, inamyloid, thin- walled; Siccus-type broom cells absent on stipe surface. Clamp connections present in all tissues.

Habit, habitat and known distribution: Scattered to solitary on dicotyledonous leaves, Malaysia and Northern Thailand.


Description author: Image Sharer (Request Authorship Credit)
Description editor: Joseph D. Cohen


Created: 2018-11-20 04:54:30 PST (-0800) by Image Sharer (image sharer)
Last modified: 2019-09-27 20:04:18 PDT (-0700) by Image Sharer (image sharer)
Viewed: once, last viewed: 2018-11-20 04:54:31 PST (-0800)