ウブゲオチエダタケ

Mycena brevicapillata Har.Takah., Mycoscience 41: 545-549, 2000　

傘と柄の表面が産毛に被われるクヌギタケ属の仲間です。毛状細胞はケブカちゃんの仲間のように厚壁にはなりません。北米産 Mycena aciculata (A.H. Sm.) Desjardin & E. Horak に外観が似ています。

肉眼的特徴: 傘は径 4-7 mm, 最初半球形, のち饅頭形になり, 平坦もしくは周縁に微かに

溝線を表す; 表面は全体に無色の微毛を帯び, 最初褐色, のち周縁に向かってやや淡色にな

る.　肉は薄く (傘の中央部において 0.5 mm 以下), 白色, 特別な味や匂いはない. 柄は 15-

40×0.5-1.5 mm, ほぼ上下同大, しばしば根本が僅かに拡大し, 中心生, 中空; 表面は白色, 全

体に無色の微毛に被われる. ヒダは上生, 疎, 柄に到達するヒダは 15-18, 幅 1 mm以下, 白

色, 縁部は平坦, 縁取りを欠く.

顕微鏡的特徴: 担子胞子は 6-7.5×4.5-5 μm, 楕円形～類球形, 表面は平坦, 無色, 非ア

ミ ロイド, 薄壁. 担子器は 19-30×6-9 μm, こん棒形, 2胞子性. 縁シスチジア及び側シスチジ

アを欠く. 傘表皮の菌糸は匍匐性, 幅 3-14 μm, 平行に配列し, 円柱形, 平坦, 黄褐色の液胞

型色素を有し, 薄壁, 非アミロイド. 傘の皮嚢体は散生し, 直立し, 紡錘形またはフラスコ型, 30-

120×6-14 μm, 無色, 平坦, 非アミロイド, 薄壁. 上表皮下層の菌糸は黄褐色の液胞型色素を

有し, 指状突起に被われ, 無色または淡褐色, 薄壁, 弱偽アミロイド. 上表皮下層の菌糸は無色で,

ミセナ構造 (図C, 実質の大部分は偽柔組織状で, 並列した短形の菌糸細胞が著しく肥大し,

偽アミロイドに染まる) を成す. 柄の皮嚢体は傘と共通するがやや小型 (20-80×5-10 μm).

全ての組織において菌糸はクランプを欠く.

供試標本: KPM-NC0005072 (基準標本), on dead branch of H. involucrata, Mt.Takao,

Hachiouji-shi, Tokyo, 7 Jul. 1999; on dead branch of H. involucrata, Mt.Takao, Hachiouji-shi,

Tokyo, 19 Aug. 1999; ibid. 29 Sept. 1999.

コメント: 褐色の傘と白色の柄は微毛を被り, ２胞子性の担子器を持ち, 子実層にシスチジア

を欠く. 東京都高尾山のタマアジサイの落枝上に発生.

褐色の傘と非アミロイドの担子胞子を持つ性質に基づき, 暫定的にウスズミコジワタケ節

Sect. Hiemales に置いたが, 縁シスチジアを欠き, 傘と柄の表皮が毛状の上皮シスチジアに被

われる特徴は明らかに本節として異質であり, 将来的に本種を収容するための独立した分類

群が設立される可能性が高い.

Mycena brevicapillata Har.Takah., Mycoscience 41: 545-549, 2000　　　　　　

Pileus 4-7 mm in diam, at first convex then plano-convex, smooth or slightly striatulate

at margin, finely puberulous overall, evenly colored brown (7E7-7E8 to 8F7-8F8) when young,

then somewhat paler toward the margin. Flesh thin (up to 0.5 mm thick), white, soft; odor

and taste indistinct. Stipe 15-40×0.5-1.5 mm, almost equal, often slightly enlarged at the

base, central, terete, hollow, white, smooth, finely puberulous overall, denser toward the

insititious base. Lamellae adnexed, distant (15-18 reach the stipe), up to 1 mm broad, thin,

white; edges even, concolorous.

Basidiospores 6-7.5×4.5-5 μm, ellipsoid to subglobose, smooth, colorless, inamyloid, thin-

walled. Basidia 19-30×6-9 μm, clavate, two-spored. Basidioles clavate. lamella-edge

fertile. Cheilocystidia and pleurocystidia absent. Hymenophoral trama regular to subregular;

element hyphae 4-11 μm wide, cylindric, often inflated, smooth, colorless, inamyloid, thin-

walled; element cells of subhymenial layer 7-20×1.5-2.5 μm, filiform, parallel each other.

Pileipellis a cutis of parallel, repent hyphae 3-10 μm wide, cylindric, smooth, with yellowish

brown (5E6-5E7) vacuolar pigment, inamyloid, thin-walled; dermatocysts scattered, suberect

to erect, fusiform or sublageniform, 30-120×6-14 μm, smooth, colorless, inamyloid, thin-

walled; underlying hyphae parallel, with yellowish brown (5E6-5E7) vacuolar pigment,

dextrinoid, with short and inflated cells up to 27 μm wide. Stipitipellis a cutis of parallel,

repent hyphae 2-5 μm wide, filiform, smooth, colorless, inamyloid, thin-walled; dermatocysts

similar to those of the pileus but smaller (20-80×5-10 μm). Stipe trama composed of

longitudinally running, cylindric hyphae 5-10 μm wide, smooth, colorless, dextrinoid, thin-

walled. Clamp connections absent in all tissues.

Known distribution: Japan (Tokyo).

Habitat: Solitary to caespitose, on dead branch of Hydrangea involucrata Sieb., from July

to September, not common.

Holotype: KPM-NC0005072, on dead branch of H. involucrata, Mt.Takao, Hachiouji-shi,

Tokyo, 7 Jul. 1999.

Other specimens examined: on dead branch of H. involucrata, Mt.Takao, Hachiouji-shi,

Tokyo, 19 Aug. 1999; ibid. 29 Sept. 1999.

Japanese name: Ubuge-ochiedatake.

Notes: This species is distinct in its finely pubescent pileus and stipe, the inamyloid

basidiospores associated with two-spored basidia, the absence of hymenial cystidia, the non-

diverticulate elements in the cortical layer of pileus and stipe, and the habitat on dead

branches of Hydrangea involucrata Sieb. The adnexed lamellae and the inamyloid

basidiospores suggest placement of this taxon in the section Hiemales Konrad & Maubl.,

subsection Hiemales Maas Geest. (Maas Geesteranus, 1980, 1991). However, its long,

fusiform or sublageniform dermatocysts covering the whole basidioma distinguish this taxon

from all previously described taxa of the section Hiemales.

In its inamyloid basidiospores, hair-like dermatocysts, and lignicolous habitat, the new

species is comparable with several taxa in the section Longisetae A.H.Sm. ex Maas Geest.

(Maas Geesteranus, 1983), such as north temperate Mycena longiseta Hohn. (Maas

Geesteranus, 1983; Pegler, 1986), Mycena tenuisetosa Corner (Corner, 1994), Mycena

brevisetosa Corner (Corner, 1994), and Mycena brunneisetosa Corner (Corner, 1994), the

latter three from Malaysia. Mycena longiseta differs in forming ventricose cheilocystidia,

diverticulate pileipellis elements, and thick-walled dermatocysts. The three Malaysian taxa

differ primarily in forming a distinct basal disk to the stipe and collariate lamellae. In addition,

M. tenuisetosa has clavate, tuberculate-echinulate cheilocystidia and pileocystidia, and, M.

brevisetosa and M. brunneisetosa have very thick-walled dermatocysts, and echinulate

pileipellis elements.