Marasmius bambusinus Fr.
Creators: name: S, Jadson José
name: Oliveira, ouza de
name: Capelari, Marina
name: Margaritescu, Simona
name: Moncalvo, Jean-Marc
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Agaricales
Marasmiaceae
Marasmius
Marasmius bambusinus

description: Marasmius bambusinus (Fr.) Fr.
(Figs 6A; 7)
Epicrisis Systematis Mycologici, seu Synopsis Hymenomycetum: 385 (Fries 1838). — Type: Brazil. Not located inSinger (1976), whereabouts unknown, Beyrich.
Agaricus bambusinus Fr., Linnaea 5: 507 (Fries 1830).
Chamaeceras bambusinus (Fr.) Kuntze, Revisio generum plantarum (Leipzig) 3 (3): 455 (Kuntze 1898).
EXAMINED MATERIAL. — Brazil. São Paulo State, São Paulo City, Parque Estadual das Fontes do Ipiranga, 3.III.2011, J.J.S. Oliveira & F. Karstedt JO343 (SP[SP 445503]!).
HABIT AND SUBSTRATE. — Marasmioid (Fig. 6A), gregarious, on a mix of dead sticks, small twigs, tendril and leaves of eudicotyledonous plant or petioles and culm-like sticks in the forest litter.
DISTRIBUTION. — Marasmius bambusinus was originally described from Brazil as Agaricus bambusinus Fr. (Fries 1830), later combined in Marasmius (Fries 1838). It was reported again from Brazil (Pernambuco State) and also from Bolivia, Colombia and Venezuela (Singer 1976). This is the first record from the São Paulo State.
DESCRIPTION
Pileus (Figs 6A; 7A)
2-13 mm diam., mostly hemispheric to convex, or campanulate, shallowly or deeply sulcate, center flat or slightly depressed, margin decurved, edge entire or slightly crenate, with rare lacerations; brightly orange to fulvous (N 20 Y 80-99 M 50-60), also pallescent orange (N 00 Y 40-60 M 20-30), center deep orange to brownish, ferrugineus orange (N 50 Y 99 M 60); membranous, context thin (<1 mm); glabrous, semi humid to dry, dull, subvelutinous, non-hygrophanous.
Lamellae (Figs 6A; 7A)
Free to mainly adnexed, distant, L = 8-9, equal, simple, l = 0, opaque, smooth, pale cream (N 00 Y 10 M 10), edge even, nonmarginate, interlamellar hymenium concolorous with the lamellae faces or partly with the pileus.
Stipe (Figs 6A; 7A)
7-22 × 0.2-0.4 mm, central, often curved, filiform, thin, equal, with circular caliber, chitinous, flexible, hollow; apex concolorous with the lamellae faces, then becoming pale ochraceous (N 40 Y 99 M 50 to N 50 Y 99 M 50) to dark brown downwards, glabrous, smooth, with a silky bright; with a scanty, off-white, tomentose basal mycelium.
Odor
Not distinctive.
Basidiospores(Fig. 7B)
16-21 × 3.5-4 µm (xm = 17.8 [± 1.3] × 3.8 [± 0.1] µm, Qm = 4.7 [± 0.3], n / s = 30/1), oblong, clavate to rarely subfusoid, smooth, hyaline, thin-walled, inamyloid.
Basidia (Fig. 7C)
23-34.4 × 7.3-8.4µm, clavate, smooth, hyaline, 4-sterigmate, thin-walled, inamyloid.
Basidioles (Fig. 7D)
20-25 × 5.3-8 µm, similar to the basidia.
Pleurocystidia (Fig. 7E)
43.8-56.3(-70) × 10-16 µm, conspicuous, sometimes with base deepened in the subhymenium, clavate, some slightly capitate or solely with shallow constriction near the apex, smooth, semi translucent or fuscous, refractive, inamyloid, thin-walled at the apex, many times moderately thick-walled elsewhere.
Cheilocystidia (Fig. 7F)
Similar to the Siccus-type broom cells of the pileipellis; main body 11.3-21.3 × 5-8.8 µm, clavate to slightly turbinate, thinwalled, hyaline; setulae or diverticula apical, erect, short to somewhat long, 1.3-4.4 × 0.8-1 µm, digitiform, cylindrical or verruciform, hyaline, simple, abundant, solid, pale yellow, apex obtuse to slightly acute.
Lamellar trama
Dextrinoid, irregular, interwoven, hyphae cylindrical, 2-8.8 µm diam., regular in outline, branched, hyaline, smooth, thinwalled.
Pileus trama
Dextrinoid, irregular, very narrow, similar to the lamellar trama, hyphae 1.3-5 µm diam.
Pileipellis
Hymeniform, composed of Siccus-type broom cells (Fig. 7G), pale yellow when grouped, easily bleaching in KOH solution, becoming hyaline when isolated, abundant; main body 10-20 × 6-11.3 µm, clavate to slightly turbinate, hyaline, thinwalled; setulae apical, erect, frequently short to moderately long, 2-5.6 ×0.5-1 µm, digitiform or cylindrical, simple, solid and regular in outline, initially pale yellow, then hyaline, apex acute to almost obtuse.
Stipe trama
Dextrinoid, cortical hyphae parallel, cylindrical, 3.4-7.5 µm diam., regular in outline, smooth, thick-walled, brown to yellowish brown in KOH solution; internal hyphae 1.6- 8.8 µm diam., thin-walled, some disorganized, other parallel, smooth, branched.
Clamp connections
Present in almost all tissues, except in the cortical trama of the stipe.
REMARKS
Desjardin et al. (2000) considered M. bambusinus a synonym of either M. hypophaeus or M. ferrugineus. These three species have many overlapping morphological characteristics and there is variation of species concepts inDesjardin et al. (2000) and Singer (1976). Basidiospores in these species are quite compatible, but the pigmented lamellar edge (marginate) and the chestnut yellow to fulvous pileus was considered typical and distinctive for M. hypophaeus (Singer 1976). Marasmius bambusinus differs from M. ferrugineus (lignicolous) by a supposed substrate preference on monocotyledonous plant (originally on bamboo leaves), by thin- to thick-walled pleurocystidia, and by a bright orange(-rufescent) pileus (Singer 1976). The holotype of M. bambusinus has been reported as lost (Singer 1976; Desjardin 1989). The examined material brings emphasis for the bright orange (rufescent) pileus (Fig. 6A) and the more distant, few (paucis) lamellae (8-9), both consistent with the protologue of M. bambusinus.
Agaricus (Marasmius) ferrugineus Berk. (synonym of Marasmius ferrugineus) was described having a yellow, ferruginous (croceo-ferrugineo) pileus and few lamellae (Berkeley 1843). In Singer (1976), M. ferrugineus has 9-13 lamellae. If M. bambusinus (not well-known) is synonym of M. ferrugineus (more well known), then the former has nomenclatural priority. Based onSinger (1976), the examined material can be either M. bambusinus or M. ferrugineus, unless we consider strong enough the fine pileus color deviation and the paucity of the lamellae. Antonín et al. (2012) revised the type of M. ferrugineus and found only slightly larger (overlapping) basidiospores (18-22 × 4.5-6.0 µm) but compatible pleurocystidia ([28-]35-50[-66] × 11-17 µm). Desjardin (1989) studied one of Singer’s M. bambusinus collections (Singer B 6345) from Colombia. It is similar to JO343 but differs in having reddish lamellar edges (typical for M. hypophaeus), by growing on gramineous leaves, by having smaller basidiospores (15.2- 18.4 × 3.6-4.6 µm), and by having thin-walled, slightly smaller pleurocystidia (30-45 × 6.5-9 µm). These spores and pleurocystidia are compatible to M. gardneri though (next taxon).
Antonín et al. (2012) studied the holotype of M. ferrugineus to support the identification of the foliicolous specimen (BRNM 724480) from South Korea as M. ferrugineus. If so, there is no preference for woody substrate in M. ferrugineus. The lamellae edge concolorous with the brownish orange to reddish brown pileus is rather more consistent with M. hypophaeus (Singer 1976). Without sequences from JO343, M. bambusinus could not be analyzed along with M. ferrugineus from South Korea (Antonín et al. 2012). Pegler (1988) mentioned M. ferrugineus as a common Neotropical and pantropical species. More should be done to elucidate between M. bambusinus and M. ferrugineus, especially in sequencing collections from the Neotropics (particularly Brazil) matching the morphology and substrate. The species are then regarded as distinct herein.
Marasmius pseudobambusinus Desjardin is similar to M.bambusinus, but differs in having indistinctly sulcate pileus, smaller basidiospores (13.6-19.2 × 3.6-5.2 µm) and apically constricted pleurocystidia (Desjardin 1991).
description: Published as part of S, Jadson José, Oliveira, ouza de, Capelari, Marina, Margaritescu, Simona & Moncalvo, Jean-Marc, 2022, Disentangling cryptic species in the Marasmius haematocephalus (Mont.) Fr. and M. siccus (Schwein.) Fr. species complexes (Agaricales, Basidiomycota), pp. 91-137 in Cryptogamie, Mycologie 20 (5) on pages 100-102, DOI: 10.5252/cryptogamie-mycologie2022v43a5, http://zenodo.org/record/7829356