Macrolepiota detersa マントカラカサタケ

Macrolepiota sp. sub. nom. provis. "manto-karakasa-take" 1999 1008 (3) Kyôto Fushimi Inari in Quercus Castanopsidis forest, lisière (Japon)

ressemble à M. procera mais chapeau en boule au revêtement éclaté en étoile autour du mamelon saillant brun, café au lait, laissant apparaître un contexte beige clair, floconneux pulvérulent jusqu'à l'anneau serré au sommet du stipe, très discrètement tigré horizontalement par des écailles en zigzag brun foncé sur fond beige pâle.

Nota ; n'évoque procera que par sa grande taille et son mamelon, son pied beaucoup plus discrètement tigré, et toujours plus pâle, souvent plus élancé, chapeau plus petit et tardant à s'ouvrir. Espèce distincte ? マントカラカサタケ nom japonais provisoire.

Traduit du japonais par T. & D. Guez :

• Chapeau 10-20 cm, ovoïde puis plan et mamelonné, revêtu d'écailles brunâtres sur fond blanc, vite fugaces sauf au disque.

• Lames blanches,　éloignées du stipe, serrées.

• Pied : 15-30 cm de long, cylindrique, creux, renflé à la base, entièrement recouvert de petites écailles brunâtre, non chiné ni zébré.
  

• Anneau blanc, de grande taille, supère, coulissant.
  

• Spores 12,5-17 x 9-12,5 µm, oblongues, pseudo-amyloïdes.
  

• Ecologie: été-automne en lisières de bois, bords des chemins, pâturages, plutôt solitaire.

English Original description (Chinese collections) :
Basidiomata (Fig. 2a) medium-sized to large.
Pileus 8-12 cm in diam., ovoid to hemispherical when young, becoming convex to plano-convex with age, white to whitish, covered with scattered, greyish orange (5B5-5B6, oac688 or oac729) to light brown (6C7-6D7, oac777) patch- or crust-like squamules which are easily detachable from the pileus; disc smooth, light brown (6C7-6D7, oac777).
Lamellae free, moderately crowded, white when young, white to cream colored when mature, up to 1 cm in height, thin, with lamellulae, sometimes with brown spots on the lamellae.
Stipe whitish, subcylindrical, 13.0-15 — 1.8-2.4 cm, attenuating upwards, with tiny brownish to brown (oac721) squamules, hollow.
Annulus ascending, whitish, membranous, complex, big, with brownish patchy squamules on the underside; movable when mature.
Context white to whitish, spongy, unchanging when cut, odorless. Taste mild or indistinct.

Basidiospores (Fig. 2c) [48/2/1] 14.0-16.0 (18.0) — (9.0) 9.5-10.5 (11.0) µm, Q = (1.40) 1.43-1.67 (1.71), avQ = 1.53 ± 0.07, ellipsoid to ovoid in side view, ellipsoid in front view, thick-walled, smooth, hyaline, dextrinoid, congophilous, metachromatic in cresyl blue, with a germ pore caused by an interruption in the episporium on the rounded apex, covered with a hyalinous cap in KOH; apiculus about 1 µm long.
Basidia (Fig. 2d) 30-38 — 11-15 µm, clavate, thin-walled, hyaline, 4-spored, rarely 2-spored.
Cheilocystidia (Fig. 2e) 18-38 — 7-15 µm, clavate to broadly clavate to pyriform, rarely subfusiform, colorless and hyaline, thin-walled.
Pleurocystidia absent.
Squamules on pileus (Fig. 2b) a palisade of vertically arranged subcylindric, clampless hyphae [18-40 (55) mm in length, 7-13 (15) mm in diam.], frequently septate, rarely branched, with terminal elements slightly attenuate toward the tip, with yellowish to brownish vacuolar pigment, slightly thick-walled.
Clamp connections common at the base of basidia and cheilocystidia.

Macrolepiota detersa Z. W. Ge, Zhu. L. Yang & Vellinga sp. nov. Fig. 2
MycoBank: MB 518349

Latin diagnosis princeps :

• Pileus 8–12 cm diametro, primo ovoideus vel hemisphaericus, dein convexus vel plano-convexus, albus vel albidus, squamulis crustatis, griseolis-aurantiacis vel pallide brunneis.
  
  
• Lamellae liberae, albae, confertae.
  
  
• Stipes 13.0–15.0×1.8–2.4 cm, subcylindricus, minutus sursum, albidus, basim incrassatus. Annulus superus, albidus, membranaceus. Caro alba; sapor mitis.
  
  
• Basidia 30–38× 11–15 μm, clavata, hyalina, 4-sporigera, raro 2-sporigera.
• Basidiosporae 14.0–16.0 (18.0)×(9.0) 9.5–10.5 (11.0) μm, ellipsoideae, glabrae, hyalinae, dextrinoideae.
• Pleurocystidia absentia.
• Cheilocystidia clavata, lato-clavata vel pyriformia, raro subfusiformia, hyalina, 18–38×7–15 μm. Squamulae pilei trichoderma, apicalis hyphis erectibus, luteis vel luteo-brunneis, subcylindricis compositae. Fibulae praesentes.

• Habitatio: terrestris.
  

• Holotypus: C. L. Hou 603 (HKAS 55306), 2 Oct. 2007, Jingde County, Anhui Province, China.
  

• Etymology: “detersa” refers to the easily detachable squamules on the pileus.

• Basidiomata (Fig. 2a) medium-sized to large. Pileus 8–12 cm in diam., ovoid to hemispherical when young, becoming convex to plano-convex with age, white to whitish, covered with scattered, greyish orange (5B5-5B6, oac688 or oac729) to light brown (6C7-6D7, oac777) patch- or crust-like squamules which are easily detachable from the pileus; disc smooth, light brown (6C7-6D7, oac777). Lamellae free, moderately crowded, white when young, white to cream colored when mature, up to 1 cm in height, thin, with lamellulae, sometimes with brown spots on the lamellae.
  

• Stipe whitish, subcylindrical, 13.0–15.0×1.8–2.4 cm, attenuating upwards, with tiny brownish to brown (oac721) squamules, hollow.
• Annulus ascending, whitish, membranous, complex, big, with brownish patchy squamules on the underside; movable when mature.

• Context white to whitish, spongy, unchanging when cut, odorless. Taste mild or indistinct.

• Basidiospores (Fig. 2c) [48/2/1] 14.0–16.0 (18.0)×(9.0) 9.5–10.5 (11.0) μm, Q=(1.40) 1.43–1.67 (1.71), avQ=1.53±0.07, ellipsoid to ovoid in side view, ellipsoid in front view, thick-walled, smooth, hyaline, dextrinoid, congophilous, metachromatic in cresyl blue, with a germ pore caused by an interruption in the episporium on the rounded apex, covered with a hyalinous cap in KOH; apiculus about 1 μm long.

• Basidia (Fig. 2d) 30–38×11–15 μm, clavate, thinwalled, hyaline, 4-spored, rarely 2-spored.

• Cheilocystidia (Fig. 2e) 18–38×7–15 μm, clavate to broadly clavate to pyriform, rarely subfusiform, colorless and hyaline, thinwalled.

• Pleurocystidia absent.
• Squamules on pileus (Fig. 2b) a palisade of vertically arranged subcylindric, clampless hyphae [18–40 (55) μm in length, 7–13 (15) μm in diam.], frequently septate, rarely branched, with terminal elements slightly attenuate toward the tip, with yellowish to brownish vacuolar pigment, slightly thickwalled.
• Clamp connections common at the base of basidia and cheilocystidia.
  

• Habitat and known distribution in China: Terrestrial and saprotrophic, solitary to scattered. Distributed in eastern China. Materials examined: Anhui Province: Jingde County, Zaoyuan, bamboo forest, 2 Oct. 2007, C. L. Hou 603 (HKAS 55306, holotype).

Comments: Macrolepiota detersa is a good edible species. It is a striking species, characterized by the combination of scattered, reflexed, patch- or crust-like, easily detachable, brown squamules on the white pileal background, a relatively big membranous annulus, and clavate to broadly clavate to pyriform cheilocystidia.

Macrolepiota detersa is very similar to M. procera in morphology. However, M. procera has smaller plate-like squamules on pileus which are more closely attached to the pileus, and the stipitipellis of M. procera has conspicuous contrasting dark brown squamules compared with those of M. detersa. Microscopically, the cheilocystidia of M. procera are mainly clavate to utriform, and hyphal segments in the squamules on pileus of M. procera are longer (25–90×7–14 μm) than those of M. detersa (15–25×7–11 μm). Phylogenetically, a close relationship with M. dolichaula, not with M. procera, was suggested based on ITS sequences data set. Morphologically, M. detersa can easily be separated from M. dolichaula by forming platelike pileus squamules, and the squamules, made up of short, rarely branched filamentous hyphae.

Macrolepiota detersa was first collected and described (inedited) from Japan (Macrolepiota species "manto-karakasa-také") based on DNA sequence data (Fig. 1), and probably occurs in other East Asian countries. Macrolepiota prominens (Viv.: Fr.) M.M. Moser (in the M. mastoidea complex), originally described from Europe, comes close but differs in a protruding umbo on the pileus, a simple broad annulus, and lamellae edges which become black with age (Wasser 1993).