肉眼的特徴: 傘は径 2-6 mm, 最初半球形～饅頭形, 老成すると平開し, ほぼ平坦または周縁に向かって浅い溝線を表し; 表面は乾性, 光沢を欠き, 平滑, 最初赤褐色, のち淡褐色を呈する. 肉は非常に薄く (0.3 mm以下), 類白色, 弾力性があり, 質は強靱, 特別な味や臭い
はない. 柄は 20-50×0.2-0.5 mm, 糸状, 中心生, 強靱; 表面は全体に白色の密毛に被われ, 頂部のみ淡褐色, 他は黒褐色を帯びる; 基部の周辺に発達した菌糸体はなく, しばしば空中伸長型の毛髪状菌糸束または不稔性の柄状構造(sterile stipe)を伴う. ヒダは上生～直性, 疎 (柄に到達するヒダは 8-12), 幅 0.5 mm以下, 白色; 縁部は平坦で, 縁取りを欠く. 胞子紋は白色.
顕微鏡的特徴: 担子胞子は 6.5-8×4-5μm, [Q = length/breadth: 1.6, n = 20 spores per two specimens], 楕円形, 平坦, 無色, 非アミロイド, 薄壁. 担子器は 20-25×4.5-7μm, こん棒形, 2 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, 10-25×7-12 μm, こん棒形, 頂部に複数の短指状付属糸を有し, 無色, 非アミロイド, 薄壁またはやや厚壁. 側シスチジアはない. 子実層托実質は平列型; 菌糸は傘実質と共通するが非アミロイド. 傘表皮の菌糸は匍匐性で平行菌糸被を形成し, 幅 2.5μm, 円柱形, 褐色の顆粒状色素に被
覆され, 非アミロイド, 薄壁; 末端細胞は 12-22×8-13μm, 類円柱形～類こん棒形, 無色, 薄壁またはやや厚壁, 多数の短指状分岐物を持つ. 傘実質は非アミロイドまたは弱偽アミロイド. 柄の表皮は円柱形の菌糸 (幅 2.5-4.5μm) が平行菌糸被を成し, 褐色の顆粒状色素に厚く被わ
れ, 厚壁 (1μm), 偽アミロイド; 柄シスチジアは 60-200×4-7μm, * 剛毛体様(図E), 直立し, 円柱形, 頂部に向かって細くなり, 平坦, 無色, 偽アミロイド, 厚壁 (2μm). 柄の実質は縦に沿って配列した円柱形の菌糸 (幅 5-8μm) からなり, 無色, 偽アミロイド, 厚壁 (1μm) になるが骨格菌糸は存在しない (一菌糸型). 全ての組織において菌糸にクランプは見られない.
供試標本: KPM- NC0006566 (基準標本), Minkenno-mori, Machida-shi, Tokyo, May 21, 2000; Ikuta-ryokuchi, Kawasaki-shi, Kanagawa-ken, June 16, 2000.
コメント: 傘表皮が平行菌糸被を形成するためオチバタケ節 (Section Androsacei) に属し, 褐色の平滑な傘と微毛に被われた黒褐色の柄からなり, 厚壁で偽アミロイドに着色する剛毛体様柄シスチジアを有する. 広葉樹林内の落ち葉の堆積上またはスギの落枝上に発生. 知られている分布は東京都町田市, 神奈川県川崎市, 福島県中通り南部. 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.
* 剛毛体様シスチジア (setoid cystidia): 排泄機能を欠き, 一般に有色で, 厚壁になり, 先端部は尖った刺状 (剛毛体様, seta-like) の外観を呈する. Tubosaeta 属 (イグチ科) 及び Marasmius 属 (特にミヤマオチバタケとその近縁種)などに見られる. 外観はメチュロイドよりも
有色な骨格菌糸に類似する. 苛性カリ (KOH) により変色しない点でタバウロコタケ属 (Hymenochaete) 及びキコブタケ属 (Phellinus) に存在する剛毛体 (seta) と区別される.
Marasmius funalis Har.Takah., Mycoscience (2002) 43:343-350.
Pileus 2-6 mm in diameter, hemispherical to convex, expanding to plano-convex at maturity, nearly smooth or shallowly sulcate-striate toward the margin, dry, dull, glabrous, at first reddish brown (8-9E7-8, 8-9F7-8) overall, then pale brown at maturity. Flesh very thin (up to 0.3 mm), whitish, pliant, tough, odor and taste none. Stipe 20-50×0.2-0.5 mm, filiform, central, terete, densely hispid to strigose with white hairs, pale brown at the apex, blackish brown elsewhere; base insititious, often accompanied by filiform rhizomorphs or sterile stipes. Lamellae adnexed to adnate, distant (8-12 reach the stipe), with 0-1 series of lamellulae, up to 0.5 mm broad, white; edges even, concolorous.
Spore print pure white. Basidiospores 6.5-8×4-5μm [Q = length/breadth: 1.6, n = 20 spores per two specimens], ellipsoid, smooth, colorless, inamyloid, thin-walled. Basidia 20-25×4.5-7μm, clavate, two-spored (?); basidioles clavate. Cheilocystidia 10-25×7-12 μm,
forming a compact sterile edge, clavate, with several irregularly cylindric apical appendages 1-7×1-1.5 μm, colorless, inamyloid, thin or slightly thick-walled. Pleurocystidia none. Hymenophoral trama regular; element hyphae similar to those of the pileitrama but completely inamyloid. Pileipellis a cutis of cylindrical cells 2-5 μm wide, encrusted with brown-pigmented granules, inamyloid, thin-walled; terminal cells 12-22×8-13 μm, subcylindrical to subclavate, colorless, thin- or slightly thick-walled, with numerous cylindrical to irregularly shaped diverticula 2-7×1-2 μm. Hyphae of pileitrama 4-7 μm wide, parallel, cylindrical, monomitic, inamyloid or weakly dextrinoid, thin-walled. Stipitipellis a cutis of parallel, repent hyphae 2.5-4.5 μm wide, cylindrical, heavily encrusted with brown pigment, dextrinoid, thick-walled (up to 1 μm); caulocystidia 60-200×4-7 μm, setiform, erect, cylindrical, tapering to an acute or rounded apex, with smooth, colorless walls up to 2 μm thick, dextrinoid. Stipe trama composed of longitudinally running, cylindrical hyphae 5-8 μm wide, monomitic, with smooth, colorless walls up to 1 μm thick, dextrinoid. Clamp connections absent.
Distribution: Japan (Kanagawa, Tokyo).
Habitat: Gregarious on dead twigs of Cryptomeria japnica (L.f.) D.Don or on leaf litter in lowland forest dominated by Carpinus tchonkii Maxim. and Quercus myrsinaeflia Blume, from May to July.
Specimens examined: KPM- NC0006566 (holotype), Minkenno-mori, Machida-shi, Tokyo, May 21, 2000; Ikuta-ryokuchi, Kawasaki-shi, Kanagawa-ken, June 16, 2000.
Japanese name: Kenawatake.
Notes: Distinctive features of this species are found in the seemingly glabrous, brown pileus, the densely white-hispid, dark brown to black, insititious stipe bearing numerous setiform caulocystidia, the subclavate cheilocystidia with several finger-like apical appendages, the lack of clamp connections, and often accompanied by the filiform rhizomorphs or the sterile stipes.
Its nonhymeniform pileipellis composed of repent, interwoven elements with highly diverticulate terminal cells and its dextrinoid tramal hyphae suggest that this species belongs in the section Andosacei Kuhner of the genus Marasmius Fr., as defined by Singer (1986). Within the section, M. funalis seems to be closely related to Marasmius liquidambari Singer from Mexico (Singer, 1976) and Papua New Guinea (Desjardin and Horak 1997). The latter species, however, differs in lacking cheilocystidia, forming non-setiform, clavate to cylindric caulocystidia, and having clamp connections. European Marasmius hudsonii (Pers.: Fr.) Fr. (Antonin and Noordeloos 1993; Breitenbach and Kranzlin 1991), which belongs to the section Hygrometrici Kuhner, has superficial resemblance to M. funalis, but it differs in having a densely hairy to strigose pileus bearing inamyloid setae, non-dextrinoid tramal hyphae, and clamp connections.
