ハルノキノボリホウライタケ

Marasmiellus vernalis Har. Takah., Mycoscience 47 (5): 260 (2006)

4月～5月、温帯低地の黒松の生木樹皮に群生します。子実体の外観はムラサキヤマンバに似ていますが、子実体はより微小(傘径 3-8 mm)で色も異なります。希なきのこで、基準産地以外ではまだ見たことがありません。基準産地の唯一の基質であった黒松は伐採され、現在見ることはできません。

文献

Takahashi, H.; Degawa, Y. 2006. Two new Marasmiellus species found on the bark of living coniferous and broad-leaved trees in Japan. Mycoscience. 47(5):257-262

A Basidiospores. B Basidium and basidioles. C Cheilocystidia. D Elements of the pileipellis.

All figures from KPM-NC0005065. Bars 10µm.

ハルノキノボリホウライタケ Marasmiellus vernalis Har. Takah., Mycoscience (2006) 47(5): 257-262.　　　　

肉眼的特徴: 傘は径 3-8 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す; 表面は密に圧着した繊維状～密綿毛状, 一様に褐色を帯びる. 肉は非常に薄く (0.2 mm以下), 淡褐色, 特別な味や臭いはない. 柄は 3-6×0.5-0.7 mm, ほぼ上下同大, 中心生, やせ型, 中空; 表面は小鱗片状または繊維状～密綿毛状, 傘と同色, 頂部は淡色, 根元に白色綿毛状菌糸が見られるが基質には付着しない. ヒダは直性, 疎 (柄に到達するヒダは 6-11), 幅 0.5 mm以下, 傘より淡色; 縁部は平坦, 同色. 胞子紋は白色.

顕微鏡的特徴: 担子胞子は 9-11×5-6μm, 楕円形, 平坦, 無色, 非アミロイド, 薄壁. 担子器は 22-42×6-9μm, こん棒形, 4胞子性. 偽担子器は類こん棒形. 縁シスチジアは 25-38×5-10μm, 群生し, 類円柱形, 上部に複数の指状～珊瑚状突起 (長さ 2-7μm)を具え, 無色, 薄壁. 側シスチジアはない. 傘の表皮は平行菌糸被で, 発達の悪いRameales構造が見られる; 菌糸は幅 3-7μm, 錯綜し, しばしば不規則に配列し, 円柱形, 断片的に少数の短指状突起が存在し, 褐色の粒状色素が凝着し, 薄壁. 柄の表皮にも褐色の凝着色素が存在する. 柄シスチジアはない. 実質の菌糸構成は一菌糸型. 全ての組織にクランプが存在する.

供試標本: Izumino-mori, Yamato-shi, Kanagawa-ken, April 23, 1998, coll. H.Takahashi; same place, April 26, 1999, coll. W. Ikeda & H.Takahashi; KPM-NC0008713 (基準標本),Izumino-mori, Yamato-shi, Kanagawa-ken, May 21, 2000, coll. H.Takahashi; KPM-NC0008714, same place, June 12, 2000, coll. H.Takahashi; KPM-NC0008715, same place,May 25, 2001, coll. H.Takahashi.

コメント: 子実体は微小で, 全体に褐色を帯び, 表皮組織に顕著な褐色の凝着色素が存在する. Rameales構造の発達が悪く, 傘と柄の表皮組織が有色で, 成熟時柄の根元が灰色を帯びない点において, Singer (1973, 1986) の分類概念におけるハルノキノボリホウライタケ節(sect. Dealbati (Bat.) Singer) ハルノキノボリホウライタケ亜節 (subsection Quercini Singer)に近縁と思われる. 春季 (4月～5月), クロマツの生木樹皮に発生. 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.

Marasmiellus vernalis Har. Takah., Mycoscience (2006) 47(5): 257-262.

Etymology: from Latin, vernalis = vernal.

Pileus 3-8 mm in diameter, at first hemispherical with involute margin, then plano-convex, often with slightly depressed center, at first smooth but soon radially sulcate-striate almost to the disk; surface fibrillose-tomentose to floccose-tomentose, evenly colored brown (7D7-8). Flesh very thin (up to 0.2 mm), light brown; odor and taste not distinctive. Stipe 3-6×0.5-0.7 mm, almost equal, central, slender, terete, hollow; surface furfuraceous to fibrillose-tomentose, concolorous with the pileus, paler toward the apex; base covered with white tomentum, but not attached to the substratum. Lamellae adnate, distant (6-11 reach the stipe), with 0-3 series of lamellulae, up to 0.5 mm broad, thin, paler concolorous with the pileus; edges terete, concolorous.

Spore print pure white. Basidiospores 9-11×5-6μm (Q = length/breadth: 1.8, n = 20 spores per two specimens), ellipsoid, smooth, colorless, inamyloid, thin-walled. Basidia 22-42×6-9μm, clavate, four-spored. Basidioles subclavate. Cheilocystidia 25-38×5-10μm, abundant, subcylindrical, with a variable number of digitate, 2-7μm long projections especially 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 poorly developed Rameales-structure; constituent hyphae 3-7 μm wide, interwoven, often irregularly arranged, cylindrical, infrequently with finger-like protuberances, encrusted with granules of brown pigment, thin-walled. Hyphae of pileitrama 2-7μm wide, subparallel or irregularly arranged, cylindrical, smooth, with intercellular pale brown pigment, inamyloid, thin-walled. Stipitipellis a cutis of parallel, repent hyphae 2-6 μm wide, cylindrical, encrusted with granules of brown pigment, inamyloid, thin-walled; caulocystidia none. Stipe trama composed of longitudinally running, cylindrical hyphae 3-9 μm wide, unbranched, smooth, with intercellular pale brown pigment, inamyloid, thin-walled. All tissues with clamp connections.

Known distribution: Japan (Kanagawa).

Habitat: Solitary to caespitose, on the living bark of Pinus thunbergii Parl., from April to June.

Specimens examined: Izumino-mori, Yamato-shi, Kanagawa-ken, April 23, 1998, coll. H.Takahashi; same place, April 26, 1999, coll. W. Ikeda & H.Takahashi; KPM-NC0008713 (holotype), Izumino-mori, Yamato-shi, Kanagawa-ken, May 21, 2000, coll. H.Takahashi; KPM-

NC0008714, same place, June 12, 2000, coll. H.Takahashi; KPM-NC0008715, same place, May 25, 2001, coll. H.Takahashi.

Japanese name: Haruno-kinobori-houraitake.

Notes: This species is characterized by its small, brown, sulcate-striate pileus, the subcylindrical cheilocystidia with a variable number of digitate projections, the mostly non-diverticulate pileipellis elements with encrusted with granules of brown pigment, and the basidiome formation on the bark of living Pinus thunbergii Parl. in spring. Its brown base of the stipe and its poorly developed Rameales-structure in the pileipellis suggest that this species belongs in the subsection Quercini Singer of the section Dealbati (Bat.) Singer (Singer 1973, 1986).

Marasmius brunneigracilis Corner, recently described from Singapore (Corner 1996), seems to be closely related to M. vernalis. The former species, however, differs in having a much larger, dark brown pileus, a wholly scurfy pruinose stipe, subdistant lamellae (14-17 reach the stipe), and clavate to ventricose or pyriform cheilocystidia. Marasmiellus pachycraspedum Noordeloos from Netherlands (Antonin and Noordeloos 1993; Noordeloos 1977) is also similar in appearance but differs in having a not sulcate-striate pileus, much shorter (6.5-8 μm) basidiospores, clavate to subfusiform, brown-encrusted cheilocystidia, and terrestrial habitat.