コゲチャベニヒダタケ
Pluteus phaeocephalus Har. Takah., Mycoscience 42: 347-353, 2001
欧州産 Pluteus plautus (Weinm.) Gill.の褐色型に酷似しますが、分布域が離れているため地理的種として分化している確率が高いと推測されます。
肉眼的特徴: 傘は径 18-23 mm, 最初半球形, のち平開し, 中丘を欠き,平坦もしくは中央部
に畝状のシワを表し, 周縁に溝線を欠き, 吸水性, 時に表皮に細かい亀裂を生じ, 最初平滑, の
ち密綿毛状, 一様に暗褐色を帯びる. 肉の厚さは 1 mm以下, 白色, 特別な味や臭いはない.
柄は 50-65×1.5-2.5 mm, ほぼ上下同大, 時に基部がやや拡大し, 中心生, 痩せ型, 中空, 白
色, 暗褐色の小鱗片を密布し, 基部に発達した菌糸体は見られない. ヒダは離生, やや密 (柄
に到達するヒダは 30-38), 幅 1 mm以下, 最初白色, のち汚ピンク色; 縁部は平坦で, 縁取りを
欠く.
顕微鏡的特徴: 担子胞子は 5.5-7×5-6μm [Q = length/breadth: 1.10-1.16], 類球形～広
楕円形, 表面は平坦, 無色, 薄壁. 担子器は 20-27×6-8μm, こん棒形, 4胞子性. 縁シスチジ
アは 25-55×10-25μm, 群生し, こん棒形～紡錘形または小のう形 (utriform), 無色, 薄壁. 側
シスチジアは 45-75×18-32μm, 散生し, 紡錘形または小のう形 (utriform). 子実層托実質の
構造は逆散開型. 傘表皮の菌糸は子実層状被を形成し, 円柱形, 狭こん棒形または狭紡錘
形, 50-120×8-22 μm, 褐色の液胞型色素を有し, 薄壁. 柄シスチジアは 25-63×10-20μm,
小のう形 (utriform) または狭こん棒形～中央部がやや括れた広こん棒形, 褐色の液胞型色
素を有し, 薄壁. 全ての組織において菌糸はクランプを欠く.
供試標本: KPM-NC0006556 (基準標本), Maruyama, Iriuda, Odawara-shi, Kanagawa-ken,
23 Apr. 2000, coll. H.Takahashi; the same place, 30 Apr. 2000, coll. H. Takahashi; the same
place, 15 Sept. 2000, coll. H.Takahashi.
コメント: 子実体は暗褐色, ビロ－ド状の傘と暗褐色の細鱗片に被われた柄からなり, 傘の
表皮は円柱形～やや紡錘形の末端細胞が柵状構造を形成する. 神奈川県小田原市入生田
のコナラの落枝上に発生.
Pluteus phaeocephalus Har. Takah., Mycoscience 42: 347-353, 2001
Pileus 18-23 mm in diam, at first hemispherical, then plano-convex or applanate, not
umbonate, smooth or sometimes irregularly wrinkled at center, not sulcate, hygrophanous,
sometimes with minutely cracking surface, glabrous when young, entirely velvety-tomentose
at maturity, persistently dark brown (7F7-8 to 8F7-8) overall. Flesh up to 1 mm thick, white;
odor and taste not distinctive. Stipe 50-65×1.5-2.5 mm, almost equal but sometimes
subbulbous or slightly swollen at the base, central, slender, terete, hollow, white, densely
covered with dark brown (7F7-8 to 8F7-8) punctate scales; basal mycelium none. Lamellae
free, moderately crowded (30-38 reach the stipe), up to 1 mm broad, thin, at first white,
then sordid pink; edges even, concolorous.
Basidiospores 5.5-7×5-6μm [Q = length/breadth: 1.10-1.16], subglobose to broadly
ellipsoid, smooth, colorless, thin-walled. Basidia 20-27×6-8 μm, clavate, four-spored.
Basidioles clavate. Cheilocystidia 25-55×10-25 μm, abundant, clavate to fusiform or
utriform, colorless, thin-walled. Pleurocystidia 45-75×18-32 μm, scattered, fusiform or
utriform. Hymenophoral trama inverse; element hyphae similar to those of the pileitrama.
Pileipellis a hymeniform layer of cylindric, narrowly clavate or narrowly fusiform terminal
elements, 50-120×8-22 μm, with a brownish vacuolar pigment, thin-walled. Hyphae of
pileitrama 3-10 um wide, interwoven, cylindric, often branched, colorless or a few with a
brownish vacuolar pigment, smooth, thin-walled. Stipitipellis a cutis of parallel, repent hyphae
3-8 μm wide, cylindric, smooth, colorless, thin-walled; caulocystidia 25-63×10-20 μm,
abundant, utriform or narrowly clavate to broadly clavate with median constriction, with a
brownish vacuolar pigment, thin-walled. Stipe trama composed of longitudinally running,
cylindric hyphae 10-18 μm wide, unbranched, smooth, colorless, thin- walled. Clamp
connections absent.
Known distribution: Japan (Kanagawa).
Habitat: Solitary, on dead fallen twigs of Quercus serrata, from April to September, not
common.
Specimens examined: KPM-NC0006556 (holotype), Maruyama, Iriuda, Odawara-shi,
Kanagawa-ken, 23 Apr. 2000, coll. H.Takahashi; the same place, 30 Apr. 2000, coll. H.
Takahashi; the same place, 15 Sept. 2000, coll. H.Takahashi.
Japanese name: Kogecha-benihida－take.
Notes: This species is characterized by its dark brown, velvety pileus, the white stipe
densely covered with dark brown punctate scales, the hyaline, utriform to fusiform
cheilocystidia and pleurocystidia, the pileipellis consisting only of cylindrical to subfusiform
elements. The combination of these features suggests that it is a member of the section
Celluloderma Fayod, the subsection Hispidodermini (Fayod) Vellinga & Schreurs (Vellinga,
1990; Vellinga and Schreurs, 1985).
Within the subsection Hispidodermini, P. phaeocephalus appears to be closely related to
several taxa with a dark brown pileus, such as Pluteus aethalus (Berk. & M.A.Curtis) Sacc.
from neotropical regions (Pegler, 1983; Singer, 1956, 1958), Pluteus brunneopunctus Horak
from Argentina (Horak, 1964), Pluteus escharites (Berk. & Broome) Sacc. from East Africa
(Pegler, 1977) and Sri Lanka (Pegler, 1986), and Pluteus striatocystis Pegler from East
Africa (Pegler, 1977). Pluteus aethalus differs from P. phaeocephalus in having brownish
black lamella edges and much larger cheilocystidia (50-110×8-18 μm: Pegler, 1983) with a
fuscous brown vacuolar pigment. Pluteus brunneopunctus differs in having broadly fusiform
pileocystidia with an acute apex and cylindric, much longer cheilocystidia (80-95 μm: Horak,
1964). Pluteus escharites differs in having a white, fibrillose-striate stipe, and lacking
pleurocystidia. Pluteus striatocystis differs in having a pale greyish white, glabrous stipe and
pleurocystidia with thickened walls in the median region.