ヒロハアマタケ

Collybia (Gymnopus) effusa Har. Takah., Mycoscience 42: 339-345, 2001　

子実体は中～やや大形(傘径 30-50 mm)で、傘表面は赤褐色を帯び成熟時明瞭な溝線を表し、柄の表面は白色の著しい粉状～小鱗片状を呈し、ヒダは粗で白色、時に淡緑黄色を帯びる。材上生。一般に群生し、目立つきのこです。

疏褶金錢菇と呼ばれる中国産 Collybia effusaは、色と形質が微妙に異なり、別種の可能性があります。

肉眼的特徴: 傘は径 30-45 mm, 最初半球形で縁部は内側に巻き, のち饅頭形からほぼ平開し, しばしば中央部がやや凹み, 最初平坦であるがまもなく放射状に走る明瞭な扇状の溝線を表し, 最初白色粉状, のち次第に平滑になり, 幼時赤褐色のち縁部に向かって淡色になる.　肉は相対的に薄く (傘の中央部において厚さ 3mm 以下), 白色, 特別な味や臭いはない. 柄は 30-55×1-3 mm, ほぼ上下同大, 中心生, 痩せ型, 中空, 白色, 全体に著しい粉状を呈し, 基部は白色綿毛状菌糸体に被われる. ヒダは上生～やや垂生し, 疎, 柄に到達するヒダは 13-18, 幅 5 mm以下, 白色または時に緑黄色～淡緑色を帯び, 縁部は平坦, 縁取りを欠く. 胞子紋は白色.

顕微鏡的特徴: 担子胞子は 7-8.5×3.5-4μm [Q = length/breadth: 2.1], 楕円形, 平坦, 無色, 非アミロイド, 薄壁. 担子器は 28-38×7-8μm, こん棒形, ４胞子性. 偽担子器はこん棒形.

縁シスチジアは 22-60×4-8μm, 群生し, 類円柱形, 平坦または複数の瘤状突起を有し, 無色, 薄壁. 側シスチジアはない. 子実層托実質は不規則に配列する; 菌糸は傘実質と共通する. 傘の表皮は平行菌糸被で, 匍匐性の菌糸が不規則に配列し, 瘤状突起に著しく被われることはない; 菌糸は幅 3-8μm, 錯綜し, 円柱形, 平坦もしくは少数の瘤状～短指状突起に被われ, 褐色の粒状色素に被覆され, 薄壁, 時に隔壁にクランプを持つ. 柄シスチジアは 35-60×6-10 μm, 群生し, 屈曲した円柱形, 平坦もしくは少数の瘤状分岐物を有し, 無色, 薄壁. 実質の菌糸はしばしば隔壁にクランプを有する.

供試標本: KPM-NC0005067 (基準標本), Mt.Takao, Hachiouji-shi, Tokyo, 15 Jul. 1999, coll. W. Ikeda & H.Takahashi; the same place, 7 Jun. 1999, coll. W.Ikeda & H.Takahashi; the same place, 5 Nov. 1999, coll. W.Ikeda & H.Takahashi; the same place, 29 Jun. 2000, coll. H.Takahashi.

コメント: 子実体はモリノカレバタケ属としては大型で, しばしば群生し, 明瞭な放射状の溝線を表す褐色の傘と, 白色または緑黄色の粗いヒダ，そして白色, 粉状の柄を有する. 東京都高尾山のスギ及びムラサキシキブの落枝上に発生. 標本は神奈川県立生命の星・地球博物館の標本庫(KPM)に登録, 収蔵されている.

本種は, 傘表皮の菌糸の特徴, 胞子の生化学的性質および生態に基づき, Antonin and Noordeloos (1997) の定義による Gymnopus 属に置くべき種類と考えられる.

Collybia　effusa　Har. Takah., Mycoscience 42: 339-345, 2001　　　　　　　　　　

Pileus 30-45 mm in diam, at first hemispherical with involute margin, then plano-convex to plane, often with slightly depressed center, at first smooth but soon radially plicate to sulcate-striate almost to the disk, at first white pruinose, glabrescent in age, evenly colored reddish brown (8D7-8 to 9D7-8) when young, then paler toward the margin. Flesh thin (up to 3 mm), white; odor and taste not distinctive. Stipe 30-55×1-3 mm, almost equal, central, slender, terete, hollow, white, pruinose to flocculose overall; base covered with white tomentum. Lamellae adnate to subdecurrent, distant (13-18 reach the stipe), up to 5 mm broad, moderately thin, white or sometimes yellowish green (30A5) to light green (30A6); edges even, concolorous.

Spore print pure white. Basidiospores 7-8.5×3.5-4 μm [Q = length/breadth: 2.1], ellipsoid, smooth, colorless, inamyloid, thin-walled. Basidia 28-38×7-8 μm, clavate, four-

spored. Basidioles clavate. Cheilocystidia 22-60×4-8 μm, abundant, subcylindric, smooth or sometimes with a variable number of outgrowths, colorless, thin-walled. Pleurocystidia absent. Hymenophoral trama irregular; element hyphae similar to those of the pileitrama. Pileipellis a layer of repent, branched hyphae, not distinctly diverticulate, not radially arranged; constituent hyphae 3-8 μm wide, interwoven, cylindric, smooth or with a few warty or finger-like protuberances, encrusted with granules of brown pigment, thin-walled, occasionally with clamped septa. Hyphae of pileitrama 3-8 μm wide, interwoven, cylindric, with smooth, slightly thickened walls up to 0.5 μm, colorless, inamyloid, occasionally with clamped septa. Stipitipellis a cutis of parallel, repent hyphae 3-10 μm wide, cylindric, smooth, thin-walled, colorless, inamyloid, with clamped septa; caulocystidia 35-60×6-10 μm, abundant, often flexuous, cylindric, smooth or with a few knob-like diverticula. Stipe trama composed of longitudinally running, cylindric hyphae 3-8 μm wide, unbranched, smooth, slightly thick-walled (up to 0.5 μm thick), colorless, inamyloid, occasionally with clamped septa.

Known distribution: Japan (Tokyo).

Habitat: Solitary to caespitose, on dead twigs of Cryptomeria japonica and Callicarpa japonica, from June to November, not common.

Specimens examined: KPM-NC0005067 (holotype), Mt.Takao, Hachiouji-shi, Tokyo, 15 Jul.1999, coll. W. Ikeda & H.Takahashi; the same place, 7 Jun. 1999, coll. W.Ikeda & H.Takahashi; the same place, 5 Nov. 1999, coll. W.Ikeda & H.Takahashi; the same place, 29 Jun. 2000, coll. H.Takahashi.

Japanese name: Hiroha-amatake (first collected and named by Mr.Minoru Aoki).

Notes: This species is characterized by its distinctly sulcate-striate pileus, the conspicuously white pruinose to flocculose stipe, distant lamellae, and its habitat on dead

twigs. The non radial arrangement of its pileipellis elements without a distinct Rameales-structure (Dryophila-structure) suggest that this species belongs in the section Levipedes (Fr.) Quel. (Antonin and Noordeloos, 1997; Halling, 1983; Singer, 1986), where it appears to be closely related to Collybia subcyathiformis (Murrill) Pegler from East Africa and neotropical regions (Pegler, 1977). The latter species differs in having a dark brown pileus, a conspicuously elongated stipe, and habitat on dead leaves. Collybia effusa has superficial resemblance to two taxa of the section Vestipedes (Fr.) Quel. because of a strongly radially sulcate-striate pileus, viz. Collybia multijuga (Berk. & Broome) Sacc. from Sri Lanka (Pegler, 1986), and Collybia allegretii (De Seynes) Pegler from East Africa (Pegler, 1977). These species differ from C.effusa in forming a cutis of radially arranged hyphae in the pileipellis (Confluens-structure). North American Collybia dysodes Halling (Halling, 1983), which belongs to the section Sunfumosae Singer ex Halling, has a conspicuously plicate-sulcate pileus and distant lamellae. Collybia dysodes, however, differs in having fetid odor, a reddish brown stipe, adnate to adnexed, light brown lamellae, and a cutis of distinctly diverticulate elements in the pileipellis.

Literature cited　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

Antonín, V. and Noordeloos,M.E. 1993. A Monograph of Marasmius, Collybia and related genera in Europe. Part 1: Marasmius, Setulipes, and Marasmiellus. Lib.Bot. 8: 1-229.

Antonín, V. and Noordeloos,M.E. 1997. A Monograph of Marasmius, Collybia and related genera in Europe. Part 2: Collybia, Gymnopus, Rhodocollybia, Crinipellis, Chaetocalathus, and additions to Marasmiellus. Lib.Bot. 17: 1-256.

Halling, R.E. 1983. The genus Collybia (Agaricales) in the Northeastern United States and adjacent Canada. Mycologia Memoir 8: 1-148.

Kornerup, A. and Wanscher, J.H. 1978. Methuen handbook of colour, 3rd. ed. Methuen & Co., London.

Pegler, D.N. 1977. A preliminary agaric flora of East Africa. Kew Bulletin Add. Ser. VI. Her Majesty's Stationery Office, London.

Pegler, D.N. 1986. Agaric flora of Sri Lanka. Kew Bulletin Add. Ser. XII. Her Majesty's Stationery Office, London.

Singer, R. 1986. The Agaricales in modern taxonomy, 4th ed. Koeltz Scientific Books, Koenigstein.