クロチャオチバタケ

Marasmius nocturnus Har. Takah., Mycoscience 41: 313-321, 2000　

暗褐色の色素を持つハリガネオチバタケ節の仲間です。ヒダも暗褐色に縁取られます。発生は稀で今のところ東京都高尾山と小田原で確認されています。

Mt.Takao, Tokyo, Aug. 1998

肉眼的特徴: 傘は径 9-15 mm, 最初半球形, のち饅頭形～ほぼ平開し, しばしば中央部に細かい皺を形成し, 時に周縁部に浅い溝線を表し, 乾性, 光沢を欠き, ビロ－ド状, 老成すると白色粉状帯を表し, 原基に近い初期の段階は淡黄色～淡いオレンジ色, のち次第に褐色を帯び, 成熟時暗褐色. 肉は薄く (1 mm以下), 傘より淡色で, 特別な味や臭いはない. 柄は 30-40×0.8-1.5 mm, 円柱形で根元はやや肥大し, 中心生, やせ型, 強靱, 中空, 平滑, 頂部は白色, 下方に向かって暗褐色を帯び, 基部は発達した白色または淡褐色の長い剛毛状菌糸体に被われる. ヒダは上生, やや疎 (柄に到達するヒダは 15-19), 幅 1.5 mm, 白色, 発達した連絡脈は見られない; 縁部は平坦で, 暗褐色の縁取りがある. 胞子紋は白色.

顕微鏡的特徴: 担子胞子は 9-10.5×4-4.5 μm, 紡錘形, 平坦, 無色, 非アミロイド, 薄壁. 担子器は 18-28×5-8 μm, こん棒形, ４胞子性; 偽担子器はこん棒形. 縁シスチジアは群生し, 縁部に不稔帯を成し, 傘の上表皮細胞と同様. 側シスチジアは多生し, 25-45×4-6 μm, 円柱形～類紡錘形, しばしば屈曲し, 時に頂部に 1-2個の微突起を持ち, 無色, 偽アミロイド, 薄壁. 子実層托実質は平列型; 菌糸は傘実質に似る. 傘の上表皮はハリガネオチバタケ型(Siccus-type) の細胞からなる子実層状被を形成し, ハリガネオチバタケ型の細胞 (付属糸を除く) は 20-28.5×5-12 μm, こん棒形または不規則な形状を成し, 時に裂け目を生じ, 頂部に淡褐色の指状付属糸 (3-8×0.5-2 μm)が密生し, 細胞壁は無色～淡褐色で厚さ 1.5 μm以下, 偽アミロイド. 傘実質の菌糸は幅 4-10 μm, 平列するかまたはやや錯綜し, 類円柱形, しばしば肥大し, 無色または淡褐色の色素を有し, 偽アミロイド, 薄壁. 柄の表皮は円柱形の菌糸(幅 2-5 μm) が平行菌糸被を成し, 褐色の色素を有し, 偽アミロイド, 薄壁; 柄シスチジアはない. 柄の実質は縦に沿って配列した円柱形の菌糸 (幅 3.5-8 μm)からなり, 細胞壁は褐色で厚さ 1 μm以下, 偽アミロイド. 全ての組織において菌糸はクランプを持つ.

供試標本: KPM-NC0006512 (holotype), solitary to scattered, on leaf litter in lowland forests dominated by Pasania edulis Makino and Quercus serrata Thunb. ex Murray, Mt.Takao, Hachiouji-shi, Tokyo, 12 Aug. 1998; CBM-FB-24139, ibid. 8 Aug. 1998; CBM-FB-24140, ibid. 10 Aug. 1998; CBM-FB-24141, ibid. 2 Sept. 1998.

コメント: 傘並びに柄の表面が暗褐色を帯び, ヒダは暗褐色に縁取られ, 円柱形の側シスチジアを持つ. 東京都高尾山のマテバシイ及びコナラの落ち葉堆積上に発生．標本は神奈川県立生命の星・地球博物館 (KPM) 及び千葉県立中央博物館 (CBM) の標本庫に登録, 収蔵されている.

Marasmius nocturnus Har. Takah., Mycoscience 41: 313-321, 2000　　

Pileus 9-15 mm in diam, at first hemispherical, then plano-convex to applanate, often obtusely subumbonate, often rugose at the center, smooth or slightly sulcate-striate toward the margin, dull, dry, opaque, minutely velutinous, pruinose in age, light yellow (4A5) to reddish yellow (4A6) or light orange (5A5) to orange (5A6) at primordial stages, then brown (7D7-7D8), finally dark brown (7F7-7F8). Flesh thin (up to 1 mm), paler concolorous with the pileus, odor and taste not distinctive. Stipe 30-40×0.8-1.5 mm, cylindrical but somewhat inflated at the base, central, slender, terete, tough, hollow, shiny, glabrous, apex white, dark brown (7F7-7F8) toward the base attached by a white or brownish, strigose mycelium to the substratum. Lamellae adnexed, subdistant (15-19 reach the stipe), up to 1.5 mm broad, white, not intervenose; edges even, concolorous with the pileus.

Spore print pure white. Basidiospores 9-10.5×4-4.5 μm, fusiform, smooth, colorless, inamyloid, thin-walled. Basidia 18-28×5-8 μm, clavate, four-spored; basidioles clavate. Cheilocystidia forming a compact sterile edge, similar to pileipellis elements. Pleurocystidia numerous, 25-45×4-6 μm, cylindric to subfusoid, often flexuous or strangulated, sometimes with one or two apical mucrones, smooth, colorless, dextrinoid, thin-walled. Hymenophoral trama regular; element hyphae similar to those of the pileitrama. Pileipellis a hymeniform layer of Siccus-typed cells 20-28.5×5-12 μm, clavate or irregular in outline, sometimes lobed, with pale brown apical setulae 3-8×0.5-2 μm, with smooth, hyaline to pale brown walls up to 1.5 μm thick, dextrinoid. Tramal hyphae of pileus 4-10 μm wide, subparallel or loosely interwoven, subcylindric, often inflated, smooth, colorless or with pale brown cytoplasmic pigments, dextrinoid, thin-walled. Stipitipellis a cutis of parallel, repent hyphae 2-5 μm wide, cylindric, smooth, with brown cytoplasmic pigments, dextrinoid, thin-walled; caulocystidia absent. Stipe trama composed of longitudinally running, cylindric hyphae 3.5-8 μm wide, with smooth, brown walls up to 1 μm thick, dextrinoid. Clamps present in all tissues.

Known distribution: Japan (Tokyo).

Specimens examined: KPM-NC0006512 (holotype), solitary to scattered, on leaf litter in lowland forests dominated by Pasania edulis Makino and Quercus serrata Thunb. ex Murray, Mt. Takao, Hachiouji-shi, Tokyo, 12 Aug. 1998; CBM-FB-24139, ibid. 8 Aug. 1998; CBM-FB-24140, ibid. 10 Aug. 1998; CBM-FB-24141, ibid. 2 Sept. 1998.

Japanese name: Kurocha-ochibatake.

Notes: This species is characterized by its dark brown, minutely velutinous pileus with somewhat rugose, subumbonate disk, the dark brown marginate lamellae, the glabrous stipe with white to brownish, strigose basal mycelium, the fusiform basidiospores, the subcylindrical pleurocystidia, and the Siccus-typed elements in the pileipellis and lamella edges.

The strigose basal mycelium, the cylindrical pleurocystidia, and the Siccus-typed pileipellis elements suggest that Marasmius nocturnus belongs in the section Sicci Singer, subsection Siccini Singer, series Haematocephali Singer (Singer, 1976, 1986), where it appears to be closely related to Marasmius brunneolus (Berk. & Broome) Pegler var. fuliginosus Desjardin & E. Horak from Papua New Guinea (Desjardin and Horak, 1997) and Marasmius grandisetulosus Singer from East Africa (Pegler, 1977; Singer, 1964). Marasmius

brunneolus var. fuliginosus differs in having a strongly plicate pileus, non-marginate lamellae, an insititious stipe, and much longer basidiospores (23-26×2.5-4 μm: Desjardin and Horak, 1997). Marasmius grandisetulosus differs in having a deeply plicate-striate, glabrous, orange brown pileus, much longer basidiospores (15-21.5 μm: Pegler, 1977), and much larger pleurocystidia (31-75×6-12 μm: Pegler, 1977).

Aside from series Haematocephali, M.nocturnus has superficial resemblance to two taxa of series Atrorubentes Desjardin & Horak (Desjardin and Horak, 1997) because of a velutinous, dark brown pileus, viz, Marasmius atrocastaneus G. Stev. from New Zealand (Desjardin and Horak, 1997; Stevenson, 1964) and Marasmius umbrinus Pegler from East Africa (Pegler 1968, 1977). These species differ from M.nocturnus in lacking pleurocystidia and in having caulocystidia which form pruinosity on the stipe surface. Marasmius nocturnus is also similar to neotropical Marasmius spiculosus Singer (Pegler, 1983; Singer, 1965), but the latter is distinct in having a pubescent stipe covered with broom-cells, much longer basidiospores (11.5-16 μm: Pegler, 1983), and setae on both pileus and stipe surface.