マダラホウライタケ (別名: ベニカバイロホウライタケ)

Marasmius maculosus Har. Takah., Mycoscience (2002) 43: 343-350.

ハリガネオチバタケ節 (Section Sicci) の仲間で、傘は茶色っぽい赤橙色～赤みの強い樺色を帯び, しばしば脱色したような色の薄い部分がまだら模様を呈し、 ヒダは橙赤色の縁取りがあり、傘の表皮はやや長い指状付属糸を持つ箒状細胞からなり、基質の間に厚い菌糸マットを形成する。

肉眼的特徴: 傘は径 20-50 mm, 最初半球形のち平らに近い饅頭形, 平坦, 吸水性, ビロ－ド状, 最初全体に濃い橙赤色～帯褐赤色(紅樺色 = 濃い黄赤, マンセル: 6R 4/8.5), 老成するとやや色が薄くなり, しばしば脱色したような色の薄い部分が不規則に見られる. 肉は厚さ 1 mm以下, 傘より淡色, 特別な味や臭いはない. 柄は 50-80×1.5-2.5 mm, 円柱形, 中心生, 中空, 全体に微粉状, 頂部類白色, 頂部以外は傘と同色; 基部は発達した白色の剛毛状～綿毛状菌糸体に被われ, 落ち葉の間に厚い菌糸マットを形成する. ヒダは上生, やや疎 (柄に到達

するヒダは 14-17), 幅 5 mm以下, 白色, 僅かに連絡脈が発達する; 縁部は全縁で, 橙赤色に縁取られる. 胞子紋は白色.

顕微鏡的特徴: 担子胞子は 8.5-11×4-5 μm, 類紡錘形, 平坦, 無色, 非アミロイド, 薄壁. 担子器は不明; 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. 側シスチジアはない. 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する; ハリガネオチバタケ型の細胞 (付属糸を除く) は 20-30×7-12μm, こん棒形, 頂部に複数の長い指状付属糸 (5-20×1-3μm) を持ち, 細胞壁は赤褐色で厚さ 1μm以下, 偽アミロイド. 傘実質の菌糸は幅 5-10 μm, 平列し, 円柱形, 非アミロイドまたは弱偽アミロイド, 薄壁. 柄の表皮は円柱形の菌糸 (幅 3-5 μm) が平行菌糸被を成し, 褐色の色素を有し, 偽アミロイド, やや厚壁 (0.5μm), クランプを持つ; 柄シスチジアは 20-55×5-8 μm, 円柱形～類こん棒形, 褐色, 偽アミロイド, やや厚壁 (0.5μm). 柄の実質は縦に沿って配列した円柱形の菌糸 (幅 4-9μm) からなり, 無色, 薄壁, 偽アミロイド. 実質の菌糸はクランプを持つ.

供試標本: KPM- NC0007426 (基準標本), Iriuda, Odawara-shi, Kanagawa-ken, 15 Sept. 2000; KPM-NC0008774, the same place, 12 Sept. 2001; KPM-NC0007427, Izumi-shizenkouen, Chiba-shi, Chiba-ken, 30 Sept. 2000.

コメント: ハリガネオチバタケ節 (Section Sicci) に属し, 子実体はやや大型で, 傘は茶色っぽい赤橙色～赤みの強い樺色を帯び, しばしば脱色したような色の薄い部分が不規則に見られ, ヒダは橙赤色の縁取りがあり, 傘の表皮はやや長い指状付属糸を持つ箒状細胞からなり, 基質の間に厚い菌糸マットを形成する. 神奈川県小田原市及び千葉県千葉市の落ち葉堆積上に発生.

Marasmius maculosus Har. Takah., Mycoscience (2002) 43:343-350. 　　　

Pileus 20-50 mm in diameter, at first hemispherical to convex, expanding to plano-convex, smooth, striatulate when wet, hygrophanous, dull, velvety, when young orange red (8B7-8) to brownish red (8C7-8) overall, somewhat paler in age, distinctly mottled with pale colored spots. Flesh up to 1 mm thick, paler concolorous with the pileus, tough, odor and taste not distinctive. Stipe 50-80×1.5-2.5 mm, cylindrical, central, terete, hollow, minutely pruinose overall, whitish at the apex, concolorous with the pileus elsewhere; base covered with white, strigose mycelial hairs or tomentum attached to an extensive mycelial mat in the substratum. Lamellae adnexed, subdistant (14-17 reach the stipe), with three series of lamellulae, slightly intervenose, up to 5 mm broad, white; edges even, paler concolorous with the pileus.

Spore print pure white. Basidiospores 8.5-11×4-5μm [Q = length/breadth: 2.1-2.2, n = 20 spores per two specimens], subfusiform, smooth, colorless, inamyloid, thin-walled. Basidia not observed; basidioles clavate. Cheilocystidia forming a compact sterile edge, similar to the pileipellis elements. Pleurocystidia none. Hymenophoral trama regular; element hyphae similar to those of the pileitrama but somewhat inflated (up to 20 μm wide). Pileipellis a hymeniform layer of Siccus-type cells with long setulae, with smooth, reddish-brown walls up to 1 μm thick, dextrinoid; main cell bodies 20-30×7-12 μm, subclavate to subcylindrical; setulae 5-20×1-3 μm, cylindrical with obtuse apex, somewhat wavy in outline, rarely forked. Hyphae of pileitrama 5-10 μm wide, parallel, cylindric, monomitic, inamyloid or weakly dextrinoid, thin-walled, with clamped septa. Stipitipellis a cutis of parallel, repent hyphae 3-5 μm wide, cylindric, dextrinoid, with smooth, brownish walls up to 0.5 μm thick, with clamped septa; caulocystidia 20-55×5-8μm, cylindrical to subclavate, with smooth, brownish walls up to 0.5 μm thick, dextrinoid. Stipe trama composed of longitudinally running, cylindrical hyphae 4-9 μm wide, monomitic, smooth, colorless, thin-walled, dextrinoid, with clamped septa.

Distribution: Japan (Kanagawa, Chiba).

Habitat: Gregarious on leaf litter in Quercus-Castanopsis forests, September.

Specimens examined: KPM- NC0007426 (holotype), Iriuda, Odawara-shi, Kanagawa-ken, 15 Sept. 2000; KPM-NC0008774, the same place, 12 Sept. 2001; KPM-NC0007427, Izumi-shizenkouen, Chiba-shi, Chiba-ken, 30 Sept. 2000.

Japanese name: Madara-houraitake.

Notes: This species is characterized by its relatively large, orange red to brownish red pileus distinctly mottled with pale colored spots, the orange red marginate lamellae, the Siccus-type cheilocystidia and pileipellis cells with relatively long setulae (up to 20 μm), and its habitat on leaf litter. The white strigose basal mycelium, the Siccus-type pileipellis elements, and the lack of pleurocystidia and setae suggest that this species belongs in the section Sicci Singer, subsection Siccini Singer, series Leonini Singer, as defined by Singer (1986). Its pileus distinctly mottled with pale colored spots is unique in the genus Marasmius and a useful field character to discriminate this species from most others.

Marasmius coklatus Desjardin, Retnowati, & E. Horak, recently described from Indonesia (Desjardin et al. 2000), is most similar to M．maculous in having relatively large basidiomata and forming broom cells with long setulae (Mrs. A. Retnowati, personal communication). Marasmius coklatus, however, differs in having a dark chocolate brown pileus, remote to distant (10-15), much broader (4-12 mm), grayish-brown, nonmarginate lamellae, and numerous setiform cystidia in the pileipellis, hymenium, and stipitipellis.