キクモンクヌギタケ 

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

柄が相対的に短く、根元付近を除き柄の表面は微毛を欠き、傘と柄は白粉状を呈し、ヒダは直生～やや垂生します。 

青木実さんが和名をつけたシロアクニオイタケ(日本きのこ図版no. 1878)は、キクモンクヌギタケと恐らく同一種と思われます。

  肉眼的特徴: 傘は径 4-10 mm, 釣り鐘形で平開せず, 時に中丘を具え, 放射状の溝線を表

し, 吸水性, 半透明の条線を表し, 最初白色粉状, まもなく平滑になり, 全体に白色または中央

部が褐色を帯びる.　肉は傘の中央部において厚さ 1mm 以下, 白色, 弱い硝酸臭があり, 特

別な味はない. 柄は 7-18×0.4-1.5 mm, 円柱形, 根本が僅かに拡大し, 中心生またはやや偏

在生, やせ型, 中空; 表面は上部白色, 根本に向かって褐色を帯び, 全体に白色粉状, 根本は

剛毛に被われる. ヒダはやや垂生し, 疎, 柄に到達するヒダは 13-18, 幅 1 mm以下, 白色, 浅

い連絡脈を持ち, 縁部は粉状, 縁取りを欠く. 胞子紋は白色.

  顕微鏡的特徴: 担子胞子は 7.5-10×4-5.5 μm, 楕円形, 表面は平坦, 無色, アミロイド, 薄

壁. 担子器は 30-38×6-9μm, こん棒形, 4胞子性. 縁シスチジアは 25-53×9-14 μm, 群生

し, 紡錘形～狭紡錘形, 無色, 薄壁. 側シスチジアを欠く. 傘表皮の菌糸は匍匐性で, 幅 4-10

μm, 平行に配列し, 円柱形, 疣状～短指状突起に被われ, 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E, 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. 

柄表皮の菌糸は疣状～短指状突起に被われ, 無色または淡褐色.

実質の菌糸は偽アミロイド. 全ての組織において菌糸はクランプを欠く.

  供試標本:  KPM-NC0005073 (基準標本), on living bark of Z. serrata, Yamato-shi,

Kanagawa-ken, 27 Jun. 1999; on dead fallen twig of A. aspera, Machida-shi, Tokyo, 24 Jun.

1993; on living bark of Z. serrata, Yamato-shi, Kanagawa-ken, 11 Jun. 1998; on living bark of

C. japonica, Kawasaki-shi, Kanagawa-ken, 4 Jul. 1999.

  コメント: 幼菌の子実体は全体に白色の粉状物に被われ, 傘は放射状の溝線を表し, ヒダは

白色で短く柄に垂生する.東京都及び神奈川県のムクノキ, ケヤキ等の樹皮または落枝上に発生. 

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

  Pileus 4-10 mm in diam, conico-convex to campanulate, not applanate, sometimes

subumbonate, radially sulcate-striate almost to the disk, hygrophanous, translucent- striate,

minutely white pruinose at first, glabrous in age, white overall or often fuliginous at the

center, often with undulating marginal zone. Flesh up to 1 mm, white, fragile; odor slightly

nitrous; taste none. Stipe 7-18×0.4-1.5 mm, cylindric, slightly enlarged at the base, central

or somewhat eccentric, slender, terete, hollow, white above, fuliginous toward the base,

white pruinose over the entire length, white strigose at the base. Lamellae adnate-

decurrent, distant (13-18 reach the stipe), up to 1 mm broad, thin, white, shallowly

intervenose; edges pruinose, concolorous.

  Spore print pure white. Basidiospores 7.5-10×4-5.5 μm, ellipsoid, smooth, colorless,

amyloid, thin-walled. Basidia 30-38×6-9 μm, clavate, four-spored. Basidioles clavate.

Cheilocystidia 25-53×9-14 μm, abundant, forming a sterile lamella edge, fusoid or narrowly

fusoid to lanceolate, colorless, thin-walled. Pleurocystidia absent. Hymenophoral trama

regular; element hyphae 15-25 μm wide, cylindric, often inflated, walls thin, smooth,

colorless, dextrinoid. Pileipellis a cutis of parallel, repent hyphae 4-10 μm wide, cylindric,

covered with warty or finger-like diverticulae, walls thin, colorless or pale brownish in the

center portion of pileus, weakly dextrinoid; underlying hyphae parallel, hyaline, dextrinoid,

with short and inflated cells up to 36 μm wide. Stipitipellis a cutis of parallel, repent hyphae

4-10 μm wide, cylindric, covered with warty or finger-like diverticulae, colorless or pale

brownish in the basal portion of stipe, weakly dextrinoid, thin-walled. Stipe trama composed

of longitudinally running, cylindric hyphae 16-22 μm wide, smooth, colorless, dextrinoid.

Clamp connections absent in all tissues.

  Known distribution: Japan (Kanagawa).

  Habitat: densely gregarious, on living bark or dead fallen twig of Aphananthe aspera 

(Thunb.) Planch, Cryptomeria japonica (L.f.) D.Don, and Zelkova serrata (Thunb.) Makino,

from June to September, common.

  Holotype: KPM-NC0005073, on living bark of Z. serrata, Yamato-shi, Kanagawa-ken, 27

Jun. 1999.

  Other specimens examined: on dead fallen twig of A. aspera, Machida-shi, Tokyo, 24 Jun.

1993; on living bark of Z. serrata, Yamato-shi, Kanagawa-ken, 11 Jun. 1998; on living bark of

C. japonica, Kawasaki-shi, Kanagawa-ken, 4 Jul. 1999.

  Japanese name: Kikumon-kunugitake.

  Notes: This species is characterized by its small, white basidiomata growing on a woody

substratum, the campanulate, shallowly sulcate- striate, occasionally subumbonate pileus,

and the adnate-decurrent lamellae; microscopically by the amyloid basidiospores, the fusoid

to lanceolate cheilocystidia, the diverticulate elements in the cortical layer of pileus and

stipe, and the absence of clamp connections. The combination of these characteristics

suggests that this taxon belongs to the section Fragilipedes (Fr.) Quel., as defined by Maas

(Maas, 1980, 1988).

  Within the section, the most closely allied species is North American Mycena subcana A.H.

Sm. (Smith, 1947), which differs in forming a grayish pileus and stipe, grayish, adnexed

lamellae, and having clamp connections. Mycena apiculispora Corner (Corner, 1994) from

Solomon Islands, which may belong to the section Hiemales Konrad & Maubl., subsection

Omphaliariae Kuhner ex Maas Geest. (Maas Geesteranus, 1980), is also comparable with

Mycena chrysanthemiformis in having finely pruinose-puberulous, white basidiomata,

decurrent lamellae, absence of pleurocystidia, and lignicolous habitat. The former species,

however, differs in having inamyloid basidiospores with subapiculate apex, and long, sinuous,

ventricose-attenuate dermatocysts.