カエンオチバタケ

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

傘と柄の下部は赤橙色を帯び、柄の表面は白粉状で、ヒダは赤橙色に縁取られます。

肉眼的特徴: 傘は径 14-22 mm, 最初饅頭形, のちほぼ平開し, 通常中丘を欠き, 老成する

としばしば中盤に微細な皺を表し, 周縁部に微かな溝線を表す; 表面は乾性, 光沢を欠き, 密に

細かいベルベット状毛被があり, 最初から全体に濃い橙色を帯び, 老成するとやや退色する.

肉は薄く (0.8 mm以下), 類白色, 特別な味や臭いはない. 柄は 25-33×0.8-1.5 mm, 円柱形,

中心生, 痩せ型, しばしば偏圧し, 強靱, 中空; 表面は全体に粉状～微毛状またはベルベット

状, 頂部白色, 下方に向かって帯褐橙色から褐色を呈し, 根本付近はほぼ暗褐色; 基部は発

達した白色の長い剛毛状菌糸体に被われる. ヒダは上生, やや疎～やや密 (柄に到達するヒ

ダは 19-23), 幅 2.5 mm以下, 白色, 多少連絡脈が発達する; 縁部は全縁で, 橙色に縁取られ

る. 胞子紋は白色.

顕微鏡的特徴: 担子胞子は 8-10×3.5-4 μm, 楕円形～アーモンド形, 平坦, 無色, 非アミ

ロイド, 薄壁またはやや厚壁. 担子器は 22-25×5-7 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

ない. 子実層托実質は平列型; 菌糸は傘実質と共通する. 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 15-24×7-12 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

直立した淡橙色の指状付属糸 (2-7×0.5-2 μm) が密生し, 細胞壁は淡橙色で厚さ 1.5 μm

以下, 非アミロイドまたは有色部分は偽アミロイド. 傘実質の菌糸は幅 4-14 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, 偽アミロイド, 薄壁. 柄の表皮は円柱形の

菌糸 (幅 4-7.5 μm) が平行菌糸被を成し, 淡褐色の厚い細胞壁 (厚さ 1μm)を有し, 偽アミロ

イド; 柄シスチジアは2形: 1) 多生し, 不規則な円柱形～紡錘形, 15-60×5-12 μm, 屈曲し, 頂

部は鈍頭, 時に分岐し, 厚壁 (1μm, 蜜色), 偽アミロイド; 2) 散生し, 大型のハリガネオチバタケ

型 (Siccus-type)で頂部に数本の長い付属糸を有し, 厚壁 (1μm, 蜜色), 偽アミロイド; 付属糸

以外の細胞本体は 12-30×3-9 μm, 円柱形または不規則な外形を成す; 付属糸は 10-32×

0.5-3.5 μm, 円柱形, 鈍頭, 屈曲し, しばしば二股に分岐する. 柄の実質は縦に沿って配列した

円柱形の菌糸 (幅 7.5-12 μm)からなり, 無色, 偽アミロイド, 薄壁.

供試標本: KPM-NC0006514 (holotype), often gregarious, on leaf litter in lowland forests

dominated by Ardisia japonica (Thunb.) Blume, Castanopsis cuspidata (Thunb. ex Murray)

Schottky var. sieboldii (Makino) Nakai, Quercus salicina Blume, and Quercus acuta Thunb.

ex Murray, Zushi-shi, Kanagawa-ken, 16 Sept. 1998; CBM-FB-24137, ibid. 25 Sept. 1997;

CBM-FB-24138, ibid. 20 Jul. 1998.

コメント: 赤橙色の傘と短い密毛に被われた柄を持ち, ヒダは赤橙色に縁取られる. 照葉樹

林内落ち葉の堆積上に発生. 分布は神奈川県逗子市, 小田原市.

Marasmius opulentus Har. Takah., Mycoscience 41: 313-321, 2000　　　　　　Figs. 1, 2

Pileus 14-22 mm in diam, at first convex, then nearly plane, usually not umbonate, disk

often rugulose in age, smooth toward a somewhat striatulate margin, dull, dry, opaque,

minutely velutinous, evenly colored deep orange (6A8) to orange (6A7), fading to orange

(6A6 or 6B6-6B7). Flesh thin (up to 0.8 mm), pallid, odor and taste not distinctive. Stipe 25-

33×0.8-1.5 mm, cylindrical, central, slender, terete or compressed, tough, hollow, pruinose

to pubescent or minutely velvety overall, apex white, brownish orange (7C7-7C8) to brown

(7D7-7D8) toward a dark brown (7F8) base attached by a white, strigose mycelium to the

substratum. Lamellae adnexed, subdistant to subclose (19-23 reach the stipe), up to 2.5 mm

broad, white, more or less intervenose; edges even, concolorous with the pileus.

Spore print pure white. Basidiospores 8-10×3.5-4 μm, ellipsoid to amygdaliform,

smooth, colorless, inamyloid, thin- or slightly thick-walled. Basidia 22-25×5-7 μm, clavate,

four-spored; basidioles clavate. Cheilocystidia forming a compact sterile edge, similar to

pileipellis elements. Pleurocystidia none. Hymenophoral trama regular; element hyphae

similar to those of the pileitrama. Pileipellis a hymeniform layer of Siccus-typed cells 15-24

×7-12 μm, clavate or irregular in outline, sometimes lobed, with pale orange apical setulae

2-7×0.5-2 μm, with smooth, pale orange walls up to 1.5 μm thick, inamyloid or pigmented

portions dextrinoid. Hyphae of pileitrama 4-14 μm wide, subparallel or loosely interwoven,

subcylindric, inflated or not, smooth, colorless, dextrinoid, thin-walled. Stipitipellis a cutis of

parallel, repent hyphae 4-7.5 μm wide, cylindric, with smooth, light brown walls up to 1 μm

thick, dextrinoid. Caulocystidia of two types: 1) numerous irregularly cylindrical to fusoid

cells 15-60×5-12 μm, flexuous or strangulated, with obtuse apex, occasionally branched,

with smooth, melleous walls up to 1 μm thick, dextrinoid; 2) scattered Siccus-typed cells

with long setulae, with smooth, melleous walls up to 1 μm thick, dextrinoid; main cell bodies

12-30×3-9 μm, cylindric or irregular in outline; setulae 10-32×0.5-3.5 μm, cylindric with

obtuse apex, flexuous, often forked. Stipe trama composed of longitudinally running, cylindric

hyphae 7.5-12 μm wide, smooth, colorless, dextrinoid, thin-walled. Clamps present in all

tissues.

Known distribution: Japan (Kanagawa).

Specimens examined: KPM-NC0006514 (holotype), often gregarious, on leaf litter in

lowland forests dominated by Ardisia japonica (Thunb.) Blume, Castanopsis cuspidata

(Thunb. ex Murray) Schottky var. sieboldii (Makino) Nakai, Quercus salicina Blume, and

Quercus acuta Thunb. ex Murray, Zushi-shi, Kanagawa-ken, 16 Sept. 1998; CBM-FB-24137,

ibid. 25 Sept. 1997; CBM-FB-24138, ibid. 20 Jul. 1998.

Japanese name: Kaen-ochibatake.

Notes: This species is characterized by its entirely reddish orange pileus, the orange

marginate lamellae, the entirely pubescent to minutely velutinous stipe with white, strigose

basal mycelium, the cheilocystidia and pileipellis composed of Siccus-typed cells, and the

thick-walled, irregularly cylindric or Siccus-typed caulocystidia with long and forked setulae.

The strigose basal mycelium, the Siccus-typed pileipellis elements, and the absence of

pleurocystidia and setiform cells, and the stipitipellis anatomy suggest that Marasmius

opulentus belongs in the section Sicci Singer, subsection Siccini Singer, series Leonini

Singer (Singer, 1976, 1986).

Within the series, M. opulentus appears to be allied with several other taxa with a reddish

- or orange-colored pileus, such as Marasmius floriceps Berk. & M.A.Curtis from neotropical

regions (Singer, 1976) and Papua New Guinea (Desjardin and Horak, 1997), Marasmius

abundans Corner from Malay Peninsula (Corner, 1996), Marasmius leoninus Berk. from

South America (Singer, 1965, 1976), and Marasmius croceus G.Stev. from New Zealand

(Stevenson, 1964) and Australia (Desjardin and Horak, 1997). Marasmius floriceps and M.

abubndans differ primarily in having a plicate to sulcate-striate pileus and no caulocystidia.

Marasmius leoninus has a deeply furrowed-sulcate pileus, non-marginate lamellae, and

lignicolous habitat. Marasmius croceus has non-marginate lamellae and lacks irregularly

cylindrical caulocystia.

Aside from series Leonini, there are several similar North American taxa: Marasmius

sullivantii Mont. (Gilliam, 1976), Marasmius corrugatus (Pat.) Sacc. & Sydow var.

aurantiacus (Murrill) Singer (Singer, 1965, 1976), and Marasmius ciliatomarginatus Desjardin

(Desjardin, 1989). Marasmius sullivantii has numerous cylindric to fusiform pleurocystia and

Siccus-typed caulocystia with short setulae. Marasmius corrugatus var. aurantiacus has a

pileus with distinctly corrugated disk, a subglabrous stipe, and lignicolous habitat. Marasmius

ciliatomarginatus has a rugulose-striate pileus, much longer, clavate basidiospores (13.5-18×

3.2-4.7 μm: Desjardin, 1989), and cylindric, gloeocystidioid cheilocystidia.