フタツミカレバタケ

Marasmiellus brunneocarpus Har. Takah., Mycoscience 41: 469 (2000) [MB#466183]

傘は径4-8 mm, 最初半球形で縁部が内側に巻く小型のモリノカレバタケ型の子実体を形成しますが、根元にモリノカレバタケ属特有の綿毛状菌糸体はありません。柄の表面は白色粉状で、２胞子性の担子器を形成する性質があります。縁シスチジアは広こん棒形で珊瑚状分岐物を持ち、胞子は類円柱形で、傘と柄の表皮組織は不規則な分岐物に被われます。

肉眼的特徴: 傘は径4-8 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明瞭な放射状の溝線を表し, 密に圧着した繊維状～密綿毛状, 赤褐色～褐色, 縁部に向かって淡色になる. 肉は非常に薄く (0.5 mm以下), 白色, 特別な味や臭いはない. 柄は 8-12×0.3-1 mm, ほぼ上下同大または根本が僅かに太くなり, 中心生またはやや偏在生, やせ型, 中空, 傘より濃色であるが頂部は淡色, ほぼ全面にわたって白色粉状～密に細かい綿毛状, 根本は無毛で分化した菌糸体は見られない. ヒダは上生, 疎 (柄に到達するヒダは 15-18), 幅 1.2 mm以下, 白色; 縁部は長縁毛状(fimbriate), 縁取りを欠く. 胞子紋は白色.

顕微鏡的特徴: 担子胞子は 9-12.5×2.5-3 μm [Q = length/breadth: 3.8], 類円柱形, 平坦, 無色, 非アミロイド, 薄壁. 担子器は 28-36×4.5-6 μm, こん棒形, 2胞子性. 偽担子器はこん棒形～類こん棒形. 縁シスチジアは 27-55×12-18 μm, 群生し, こん棒形～類球形, 上部に多数の指状～珊瑚状突起 (10×3 μm)を具え, 無色, 薄壁. 側シスチジアはない. 子実層托実質はやや平列～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, Rameales構造｢多分枝菌糸構造｣ (図D)が発達する; 菌糸は幅 2.5-10 μm, 互いに平行に走り, 円柱形, しばしば肥大し, 多数の瘤状～指状突起に被われ, 菌糸の間に褐色の色素顆粒が存在し, 薄壁. 傘実質の菌糸は幅 3-13μm, 円柱形, しばしば肥大し, 薄壁, 無色, 非アミロイド. 柄の表皮は平行菌糸被; 菌糸は幅 2.5-7μm, 円柱形, 多数の瘤状分岐物に被われ, 非アミロイド, 細胞壁は褐色で厚さ 1 μmに達する. 柄の実質は縦に沿って配列した円柱形の菌糸 (幅 4-8 μm)からなり, 無分岐, 無色または淡褐色, 非アミロイド, 厚壁 (1.5 μm). 全ての組織にクランプが存在する.

生態: 神奈川県大和市のシラカシとヒサカキを中心とする林内の落枝及び落ち葉上に発生.

Marasmiellus brunneocarpus Har. Takah., Mycoscience 41: 467-472, 2000　　

Pileus 4-8 mm in diam, at first hemispherical with involute margin, then convex, finally applanate with slightly depressed center, at first smooth but soon radially grooved, minutely appressed fibrillose to felted-tomentose, reddish brown (8E6-8E7) to brown (7E6-7E7), paler toward the crenulate margin. Flesh very thin (up to 0.5 mm), white; odor and taste not distinctive. Stipe 8-12×0.3-1 mm, almost equal but sometimes subbulbous or slightly swollen at the base, central or somewhat eccentric, slender, terete, hollow, deep concolorous with the pileus, paler toward the apex, white pruinose to flocculose overall; base insititious. Lamellae adnexed, distant (15-18 reach the stipe), narrow (up to 1.2 mm broad), thin, white; edges fimbriate, concolorous.

Spore print pure white. Basidiospores 9-12.5×2.5-3 μm [Q = length/breadth: 3.8], subcylindric, smooth, colorless, inamyloid, thin-walled. Basidia 28-36×4.5-6 μm, clavate, two-spored. Basidioles clavate to subclavate. Cheilocystidia 27-55×12-18 μm, abundant, clavate to subglobose, with numerous, up to 10×3 μm, finger-like or coralloid protuberances in upper part, colorless, thin-walled. Pleurocystidia absent. Hymenophoral trama subregular to irregular; element hyphae similar to those of the pileitrama. Pileipellis a cutis with strongly developed Rameales-structure; constituent hyphae 2.5-10 μm wide, interwoven, cylindric, somewhat inflated, with abundant warty or finger-like protuberances, with granules of brown pigment among the hyphae, thin-walled. Hyphae of pileitrama 3-13 μm wide, subparallel, cylindric, somewhat inflated, walls thin, smooth, colorless, inamyloid. Stipitipellis a cutis of parallel, repent hyphae 2.5-7 μm wide, cylindric, diverticulate, with smooth, inamyloid, brown walls up to 1 μm thick. Stipe trama composed of longitudinally running, cylindric hyphae 4-8 μm wide, unbranched, with smooth, inamyloid, colorless or light brown walls up to 1.5 μm thick. Clamps present in all tissues.

Known distribution: Japan (Kanagawa).

Habitat: Solitary to caespitose, on dead leaves and twigs in lowland forests dominated by Quercus myrsinaefolia Blume and Eurya japonica Thunb., from June to September, not common.

Holotype: KPM-NC0005076, on dead leaves and twigs under broad-leaved trees, Yamato-shi, Kanagawa-ken, 15 Jun. 1998.

Other specimens examined: on dead leaves and twigs under broad-leaved trees, Yamato-shi, Kanagawa-ken, 28 Sept. 1998; ibid. 12 Jul. 1999.

Japanese name: Futatsumi-karebatake.

Notes: The collybioid basidiomata, the more than 10 μm long basidiospores, and the pileipellis with a distinct Rameales-structure suggest placement of this species in the section Tricolores Singer (Singer, 1973, 1986). Within the section, Marasmiellus brunneocarpus is closely allied with North American Marasmiellus pluvinus Redhead (Desjardin, 1987; Redhead, 1982). The latter species, however, differs in having four-spored basidia, thick-walled, clavate to vesiculose pileipellis elements with apical diverticulae, and habitat on senescent leaves of conifers. Marasmiellus ramealis (Bull.: Fr.) Singer var. macrosporus (Courtec.) Antonin & Noordel. (Antonin and Noordeloos, 1993; Courtecuisse, 1986) from France, which belongs to the subsection Ramealini Singer of the section Rameales (J.Lange) Singer, also has two-spored basidia and similar cheilocystida. This species differs from M. brunneocarpus in forming cream-pinkish to pale ochraceous basidiomata with subdecurrent lamellae, and much larger basidiospores (10-16.5×3-5 μm: Antonin and Noordeloos, 1993).

Literature

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

Antonĺn V, Noordeloos ME. 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

Courtecuisse, R. 1986. Macromycetes interessants, rares ou nouveaux IV. Tricholomatales. Doc. Mycol. 16(62): 23-46.

Desjardin, D.E. 1987. 7. Tricholomataceae. I Marasmioid fungi: the genera Baeospora, Crinipellis, Marasmiellus, Marasmius, Micromphale, and Strobilurus. In: The Agaricales

(g!lled fungi) of California (ed by Thiers, H.D.). Mad River Press, Eureka.

Singer, R. 1973. The genera Marasrniellus, Crepidotus and Sirnocybe in the Neotropics. Beih. Nova Hedwig. 44: 1-339.

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

Redhead, S.A. 1982. Fungi Canadenses 216. Marasmiellus ptuvinus. Agaric. Canada, Ottawa.

Takahashi, H. 2000. Two new species of Marasmiellus from eastern Honshu, Japan. Mycoscience. 41:467-472