スギノオチバタケ

Marasmius capitatus Har. Takah., Mycoscience 41: 539-543, 2000

脈状に退化するヒダおよび頂部頭状形のシスチジアを有する性質は Gloiocephala属に近縁であることを示唆しています。Jiao Qin博士(私信)によると、中国南西部にも近縁種が分布しているとのことです。

原記載

Takahashi, H. 2000. Two new species of Marasmius from eastern Honshu, Japan. Mycoscience. 41(6):539-543

肉眼的特徴: 傘は径 1-5 mm, 最初半球形で縁部はやや内側に巻き, のち饅頭形になり, 中丘を欠き, 老成時放射状の溝線を表し, 膜質, 乾性, 粉状, 全体に白色. 肉は非常に薄く (0.3 mm以下), 白色, 特別な味や臭いはない. 柄は 6-10×0.2-0.4 mm, 円柱形, 中心生, 糸状, 表面

は全体に粉状～細軟毛に被われ, 頂部白色, 下方に向かって暗褐色を呈し, 基部は黒色, 根本は無毛で分化した菌糸体は見られない. ヒダは直性, 疎 (柄に到達するヒダは 10以下), 幅 0.5 mm以下, 白色, 脈状に退化し, 連絡脈を持つ; 縁部は平坦, 縁取りを欠く.

顕微鏡的特徴: 担子胞子は 8-10×4-4.5 μm, 楕円形, 平坦, 無色, 非アミロイド, 薄壁. 担子器は 17-27×5-7.5μm, こん棒形, ４胞子性; 偽担子器はこん棒形. 縁シスチジアは 35-55×8-12μm, 群生し, 縁部に不稔帯を成し, 紡錘形～片脹れ状, 頂部頭状形, 平坦, 無色, 非ア

ミロイド, 薄壁. 側シスチジア散在し, 縁シスチジアと同形. 子実層托実質は不規則型. 傘の表皮は子実層状被をなし, 広こん棒形～洋梨形の細胞 (15-25×9-15 μm) からなり (Globularis-type), 無色, 非アミロイド, 薄壁またはまれにやや厚壁; 傘シスチジアは散在し, 縁シスチジアと同形. 柄シスチジアは多生し, 15-35×7-10μm, こん棒形または紡錘形～片脹れ状, 頂部頭状形, 平坦, 非アミロイド, 細胞壁は淡褐色で厚さ 1 μmに達する. 実質の菌糸は非アミロイド. 全ての組織の菌糸はクランプを持つ.

供試標本: KPM-NC0006040 (基準標本), on dead fallen leaves of Cryptomeria japonica, Mt. Takao, Hachiouji-shi, Tokyo, 25 Oct. 1999; CBM-FB-24596, on dead fallen leaves of Cryptomeria japonica, Yamato-shi, Kanagawa-ken, 16 Nov. 1999.

コメント: 子実体は白色の傘と黒褐色の毛髪状の柄からなり, ヒダは浅い脈状で, 頂部頭状形のシスチジアを持つ.

子実体の類型は Marasmius Sect.Epiphylli と共通するが, Gloiocephala 型シスチジアの存在は Sect.Epiphylli の所属種として異質であり, Gloiocephala 属に近縁であることを示唆している.

東京都及び神奈川県のスギの落ち葉上に発生.

Marasmius capitatus Har. Takah., Mycoscience 41: 539-543, 2000　　

Pileus 1-5 mm in diam, at first hemispherical to convex with a slightly involute margin, then plano-convex, not umbonate, radially rugulose in age, membranous, dry, minutely pruinose, pure white overall. Flesh thin (up to 0.3 mm), pure white, odor and taste not distinctive. Stipe 6-10×0.2-0.4 mm, cylindric, central, filiform, terete, entirely pruinose to pubescent, apex white, dark brown toward a blackish brown base; basal mycelium not seen. Lamellae adnate, distant (up to 10 reach the stipe), up to 0.5 mm broad, white, vein-like, intervenose; edges even, concolorous.

Basidiospores 8-10×4-4.5 μm, ellipsoid, smooth, colorless, inamyloid, thin-walled. Basidia 17-27×5-7.5μm, clavate, four-spored; basidioles clavate. Cheilocystidia 35-55×8-12 μm, forming a compact sterile edge, fusoid-ventricose, with capitate apex, smooth, colorless, inamyloid, thin-walled. Pleurocystidia scattered, similar to cheilocystidia. Hymenophoral trama irregular; element hyphae similar to those of the pileitrama. Pileipellis a hymeniform layer of broadly clavate to pyriform cells 15-25×9-15 μm, colorless, inamyloid, thin- or rarely thick-walled; pileocystidia scattered, similar to cheilocystidia. Hyphae of pileitrama 2-5 μm wide, loosely interwoven, filiform, not inflated, smooth, colorless, inamyloid, thin-walled. Stipitipellis a cutis of parallel, repent hyphae 2-4 μm wide, cylindric, with smooth, light brown walls up to 0.5 μm thick, inamyloid; caulocystidia numerous, 15-35×7-10 μm, clavate to fusoid-ventricose, with capitate apex, with smooth, light brown walls up to 1 μm thick, inamyloid. Stipe trama composed of longitudinally running, cylindric hyphae 3-10 μm wide, with smooth, light brown walls up to 1.5 μm thick, inamyloid. Clamps present in all tissues.

Known distribution: Japan (Kanagawa, Tokyo). Habitat: Scattered, on dead fallen leaves of Cryptomeria japonica (L.f.) D.Don, from October to November, not common.

Specimens examined: KPM-NC0006040 (holotype), on dead fallen leaves of Cryptomeria japonica, Mt. Takao, Hachiouji-shi, Tokyo, 25 Oct. 1999; CBM-FB-24596, on dead fallen leaves of Cryptomeria japonica, Yamato-shi, Kanagawa-ken, 16 Nov. 1999.

Japanese name: Sugino-ochibatake.

Notes: This species is characterized by its membranous, white pileus, the anastomosing, vein-like lamellae, the minutely pubescent, filiform stipe without basal mycelium, the capitate cystidia on the hymenium, pileus, and stipe, the hymeniform pileipellis composed of smooth elements, and the habitat on dead fallen leaves of Cryptomeria japonica.

Marasmius capitatus seems to be most closely related to Marasmius epiphyllus (Pers.: Fr.) Fr., the well-described type species of the section Epiphylli (Antonin and Noordeloos, 1993; Breitenbach & Kranzlin, 1991; Desjardin, 1987; Gilliam, 1976), and Marasmius tenuiparietalis Singer from Argentina (Singer, 1969), North America (Desjardin, 1987; Gilliam, 1976), and Europe (Antonin and Noordeloos, 1993). The latter two taxa, however, differ in their non-capitate cystidia and their habitat on leaves of broad-leaved trees. The fusoid-ventricose, capitate hymenial cystidia of M. capitatus is comparable with those of North American Marasmius felix Morgan (Gilliam, 1976), but the latter species has a light yellowish pink pileus and obovate to fusoid-elliptic basidiospores, and grows on petioles of dicotyledonous herbs.