Marasmius pallescens Murrill
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 pallescens

description: Marasmius cf. pallescens Murrill (Figs 15C; 19)
North American Flora 9 (4): 261 (Murrill 1915). — Type: Puerto Rico. Rio Piedras, 18.VIII.1912, J.R. Johnston 556 (NY[NY774585]).
EXAMINED MATERIAL. — Brazil. São Paulo State, Iporanga City, Parque Estadual Turístico do Alto Ribeira, Reserva Betary, 05.XII.2011, J.J.S. Oliveira JO426 (SP[SP 446078]!); 28.II.2012, D.E. Desjardin & C. Stevani DED8673 (SP[SP 445666]!).
HABIT AND SUBSTRATE. — Marasmioid (Figs 15C; 19A 1), gregarious, close, scattered to solitary on dried eudicotyledonous leaves and sticks in the forest litter.
DISTRIBUTION. — Originally described from Puerto Rico (Murrill 1915), it is also reported from Venezuela (Dennis 1961; Singer 1965, 1976; Pegler 1983) and Martinique (Pegler 1983). If the identity of this “ruby pink form” is confirmed as conspecific, this would be the first record from Brazil.
DESCRIPTION
Pileus (Figs 15C; 19A 1, A2)
5-15(-20) mm diam., obtusely conical to broadly convex, or plano-convex, sulcate, center flat or slightly umbonate, shallowly depressed when fully matured, margin decurved to applanate, edge entire to slightly crenate; at first ruby overall (12E7-8), then remaining ruby pink (N 30 Y 30-50 M 99) to pinkish red (N 30 Y M 90), or fainting to greyish ruby (12D6-7), with a dark purplish red (N 70 Y 40-60 M 99) or ruby (12E7-8) center; membranous, context thin (<1 mm); glabrous, dry, dull, subvelutinous, non-hygrophanous.
Lamellae (Figs 15C; 19A 1, A2)
Free to adnexed, few toothed seceding, distant, L = 6-16, equal, broad (up to 1.5 mm), slightly ventricose, simple, l = 0(-1), opaque, smooth, white, edges even, non-marginate, interlamellar hymenium paller than the pileus or ruby.
Stipe (Figs 15C; 19A 1)
19-55 × 0.3-0.8 mm, central, thick filiform, equal, or broadening toward apex, with circular caliber, chitinous, hollow; apex whitish pink (N 10 Y 20-40 M 20), abruptly becoming reddish brown (N 80 Y 99 M 60-80) to dark brown (N 90 Y 99 M 80-99), or almost black at the base, glabrous, smooth, with a silky bright; subinsititious or with a scarce, white, tomentose to strigose basal mycelium.
Odor
Not distinctive.
Basidiospores (Fig. 19B)
(11.1-)12.3-17.3 × (3.2)3.7-5 µm (xrm = 14.7-15 × 4.2 µm; xmm = 14.9 [± 0.2] × 4.2 µm; Qrm = 3.6; Qmm = 3.6; n / s = 30/2), oblong, clavate, subfusoid to fusoid, smooth, hyaline, thinwalled, inamyloid.
Basidia (Fig. 19D)
20-26.7 × 4.8-7.4 µm, clavate, smooth, hyaline, thin-walled, with four short, verruciform sterigmata, inamyloid.
Basidioles (Fig. 19C)
(15.2-)18.7-28 × (3.8-)4.5-6.9(-7.5) µm, clavate, smooth, hyaline, inamyloid.
Pleurocystidia (Fig. 19E)
31.4-47 × 7.2-10.6 µm, mostly clavate, or broadly clavate, some slightly lageniform or ventricose, sometimes apically capitate, papillate or mucronate, or with digitifom projection, occasionally wavy with shallow constrictions, smooth, hyaline to somewhat fuscous, thin-walled, refractive, inamyloid.
Cheilocystidia (Fig. 19F)
Similar to the Siccus-type broom cells of the pileipellis, but hyaline and with thinner walls; main body 7.6-19.8 × 5.2- 9.9 µm, clavate to slightly turbinate, seldom branched or lobulate, thin-walled, inamyloid; setulae apical, erect, 3.5- 7.1 × 0.5-1.1 µm, cylindrical or filiform, needle-like, regular in outline, simple, solid, hyaline, apex acute.
Lamellar trama
Strongly dextrinoid, irregular, interwoven, hyphae cylindrical, 1.2-6.1 µm diam., regular in outline, hyaline, smooth, thin-walled.
Pileus trama
Dextrinoid, similar to the lamellar trama, hyphae 2.8-6.9(- 8.7) µm diam., branched.
Pileipellis
Hymeniform, composed of Siccus-type broom cells (Fig. 19G), pale brown, but with rare more deeply pigmented cells, bleaching in KOH solution; main body 9-18.6 × 4.1-9.5(-15) µm, cylindrical thin, clavate, turbinate, sometimes almost pedicellate, pale brown, later hyaline, thin-walled to slightly thick-walled (firm-walled), inamyloid or weakly dextrinoid; setulae apical, erect, 2.5-7.7 × 0.7-1.5 µm, cylindrical or filiform, needlelike, rarely digitiform, simple, regular in outline, solid, pale brown, apex tapered, obtuse to mostly acute.
Stipe trama
Dextrinoid, some strands apparently inamyloid, stipitipellis and cortical hyphae parallel, packed, cylindrical, regular in outline, 2.6-9 µm diam., sometimes branched, smooth, those of the superficial layer highly melanized, dark chestnut brown, brown at the cortex, thick-walled; internal hyphae regular in outline, 2.6-6.8 µm diam., hyaline, thin-walled.
Clamp connections
Present in all tissues.
REMARKS
Murrill (1915) would have named Marasmius pallescens based on the pale-red pileus (5-8 mm broad), fading to isabelline on drying. Dennis (1961) reported the species from Venezuela with lilac pileus (7 mm diam.). Singer (1965, 1976) studied both the type from Puerto Rico (18 August 1912, J. R. Johnston 556) and the collection from Venezuela (20 June 1958, Dennis 117) and reported a pale red or light lilac (5-8 mm broad.) pileus when fresh (Murrill 1915; Dennis 1961), but reddish brown when dried. Pegler (1983) examined the same collections, adding a third from Dominique, and reported a “Pale Flesh Colour” pileus (5-15 mm diam.), sometimes paling to buff but retaining a slightly darker disc. All of them agreed for the campanulate sulcate pileus and distant, white, about 10 lamellae (10-14 in Pegler 1983) in the protologue. These collections from Brazil agree in nearly all characteristics but differs in the ruby pink to pinkish red (Fig. 15C), larger pileus (11-15 mm diam.). The size of the basidiospores perfectly agree with Singer (1976) and Pegler (1983), but those in Dennis (1961) are shorter (11-14 × 3.5 µm); the shape and size of pleurocystidia are nicely compatible. The size of basidia and basidioles is slightly larger in our collections. Despite the distinctions mentioned above, the examined collections match the morphological concept of the species.
Singer (1976) commented that “at first sight one might be inclined to consider this species one of the numerous color variants of Marasmius haematocephalus ”. Indeed, M. pallescens seems very similar to M. haematocephalus, especially considering these possible collections from Brazil. However, both basidiospores and pleurocystidia are clearly shorter and the lamellae are broader and ventricose in M. pallescens. This species is also similar to M. panerythrus Singer, but this later differs by having more deeply pigmented pileus (purple red with paler “copper leaf ” margin), by having marginate, pinkish lamellae, by having smaller basidiospores (13-14.7 × 3.5-4.2 µm), and by having larger pleurocystidia (20-62 × 6.8-9.8 µm) (Singer 1976).
Marasmius cf. pallescens is similar to M. pulcherripes “the pinkish-red form” (Desjardin 1989), and originally described from Nearctic (New York, United States). Marasmius pulcherripes, however, has more numerous lamellae (15-16), more colorful stipe, slightly smaller basidiospores ([10.4-]12-16 × 3.2- 4.6 µm), and regular lamellar trama. Antonín et al. (2012) reported M. pulcherripes from South Korea with marginate lamellae and larger pleurocystidia (37-65 × 7.0-12 µm), and this branched as a distinct lineage closer to M. siccus species complex (siccus_cp1) than to M. haematocephalus species complex (haemat_cp1) in Fig. 1. Unfortunately, no DNA sequences were obtained from the examined collections here as M. cf. pallescens. Because of the morphological similarity, one may predict it would branch closely related to M. pulcherripes sensu Antonín et al. (2012). Based on morphology, M. cf. pallescens is classified in ser. Pulcherripes (Oliveira et al. 2020) along with M. pallescens, M. panerythrus and M. rhodopurpureus.
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 125-126, DOI: 10.5252/cryptogamie-mycologie2022v43a5, http://zenodo.org/record/7829356