2018年7月5日更新


スミレニガイグチTylopilus obscureviolaceus Har. Takah., Mycoscience 45(6): 374 (2004) 
  肉眼的特徴: 傘は径 70-100 mm, 最初半球形, のち饅頭形〜ほぼ平開し, 縁部は最初内
側に巻く; 表面は乾性, やや密綿毛状, 幼菌から成菌に至るまで傘全体が一様に暗青紫色を
呈する. 肉は厚さ 10 mm, 固くしまり, 白色, 空気に触れても変色しない; 特別な臭いはなく, 強い
苦みがある. 柄は 80-100×20-30 mm, ほぼ上下同大または下方に向かってやや太くなり, 中
心生, 中実; 表面は乾性, やや密綿毛状, 時に縦皺を表し, しばしば上部に青紫色の繊細な網
目模様を表し, 傘より淡色または淡褐色を帯び, 根元に向かって暗色になり, 頂部は類白色; 
根本は類白色の密綿毛状菌糸体に被われる. 管孔は厚さ 8 mm以下, 直生〜やや上生, 幼時
白色, のち帯紅色, 空気に触れても変色しない; 孔口は小型 (2-3 per mm), 類角形, 縁取りは
なく, 傷つけても変色しない.
  顕微鏡的特徴: 担子胞子は 6-7.2×3.3-4 μm [Q = length/breadth: 1.8, n = 20 spores 
per two specimens], 楕円形〜やや紡錘形, イグチ型, 平坦, 帯紅色, 厚壁. 担子器は 15-20×
5-8 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, 30-40×5-10 μ
m, 類円柱形〜類紡錘形, 平坦, 無色, 薄壁. 側シスチジアは散生し, 縁シスチジアに似る. 子実
層托実質はイグチ亜型; 菌糸は幅 3-6 μm, 円柱形, 無色, 薄壁. 傘の上表皮層は緩く錯綜し
た菌糸からなる毛状被を形成する; 末端細胞は円柱形, 30-60×4-7 μm, 赤褐色の色素が細
胞内に存在し, 薄壁, 傘シスチジアはない. 傘実質の菌糸は緩く錯綜し, 円柱形, 幅 4-11 μm, 
無色, 薄壁. 柄の表皮は柄シスチジアが子実層状被を成す; 柄シスチジアは 13-19×5-7 μ
m, 広こん棒形, 平坦, 帯褐色の色素が細胞内に存在し, 薄壁. 柄の実質は縦に沿って配列した
円柱形の菌糸 (幅 4-10 μm)からなり, 時に分岐し, 無色, 薄壁またはやや厚壁 (0.5 μm以
下). 全ての組織において菌糸はクランプを欠く.
   供試標本: KPM-NC0010099 (holotype), Outomi (Iriomote Island), Taketomi-cho, Okinawa-
ken, May 31, 2002, coll. H.Takahashi.
  コメント: Singer (1986) の分類概念によるニガイグチ節 (section Tylopilus )に所属し,子実
体は中〜大型で,強い苦みがあり,傘と柄の表面は暗青紫色を呈し,柄の上部にしばしば青
紫色の繊細な網目模様を表し,担子胞子は相対的に小型 (8 μm以下)である. 北米産
Tylopilus plumbeoviolaceus (Snell & E.A.Dick) Singer 及び日本産ニガイグチモドキ Tylopilus
neofelleus Hongo は本種に最も近縁と思われるが,北米産種は傘の表面が成熟時褐色また
は灰色を帯び,紡錘形の傘シスチジアが子実層状被を形成し,担子胞子はより長形である.
一方ニガイグチモドキは傘の表面がオリーブ褐色〜帯紅褐色で,孔口は最初から青紫色に縁
取られる.
  Tylopilus plumbeoviolaceus の近縁種として最近記載された中国南部(広東省)産Tylopilus
plumbeoviolaceoides T.H. Li, B. Song & Y.H. Shen, (2002)は, 傘の上表皮層がゼラチン化する
点で紫系のTylopilus 近縁群 としては異質である. また最近中国南西部(四川省, 雲南省)から
報告された Tylopilus microsporus S.Z. Fu, Q.B. Wang & Y.J. Yao, (2006)は, 柄の表面に網目
模様を欠き, 担子胞子がやや長形な点を除いてはスミレニガイグチに極めて類似しており, 両
種の異同に関しては今後 DNA解析を含む詳細な再検討を要する.
  沖縄県西表島のスダジイとオキナワウラジロガシを中心とする照葉樹林内地上に発生.



FIg. 1.Tylopilus obscureviolaceus.

Tylopilus obscureviolaceus Har. Takah., Mycoscience 45(6): 374 (2004)   
  Etymology: Latin, obscureviolaceus = dark purple, referring to the color of basidiomata. 
   Pileus 70-100 mm in diameter, at first hemispherical, becoming broadly convex to nearly 
plane in age, with inrolled then straight margin; surface dry, subtomentose, persistently and 
evenly colored dark Magenta (13F4-8) to dark purple (14F5-8). Flesh up to 10 mm thick, 
firm, white, unchanging when cut; odor indistinct, taste very bitter. Stipe 80-100×20-30 
mm, subequal or somewhat enlarged toward the base, central, terete, solid; surface dry, 
subtomentose, sometimes longitudinally rugulose, often finely reticulated above by a thin-
veined, purplish reticulum, paler concolorous with the pileus or more brownish, darker toward 
the base, whitish at the apex; base covered with whitish mycelial tomentum. Tubes up to 8 
mm deep, adnate to slightly adnexed, white when young, dull pinkish in age, unchanging when 
cut; pores small (2-3 per mm), subcircular, concolorous, unchanging where handled.
  Basidiospores 6-7.2×3.3-4 μm [Q = length/breadth: 1.8, n = 20 spores per two 
specimens], ellipsoid-subfusiform, inequilateral with a shallow suprahilar depression in profile, 
smooth, pinkish, thick-walled. Basidia 15-20×5-8 μm, clavate, four-spored. Basidioles 
clavate. Cheilocystidia gregarious, 30-40×5-10 μm, subcylindrical to subfusiform, smooth, 
hyaline, thin-walled. Pleurocystidia scattered, similar to the cheilocystidia. Hymenophoral 
trama bilateral-divergent of the Boletus subtype; element hyphae 3-6 μm wide, cylindrical, 
smooth, colorless, thin-walled. Pileipellis a trichodermium of vertically arranged, loosely 
interwoven elements, with reddish brown (9D7) to brownish red (10D7) intracellular pigment, 
thin-walled; terminal cells cylindrical, 30-60×4-7 μm, without pilocystidia. Pileitrama 
consisting of cylindrical, loosely interwoven hyphae 4-11 μm wide, smooth, colorless, thin-
walled. Stipitipellis hymeniform, consisting of caulocystidia; caulocystidia 13-19×5-7 μm, 
broadly clavate, smooth, with intracellular brownish pigment, thin-walled. Stipe trama 
composed of longitudinally running, cylindrical cells 4-10 μm wide, sometimes branched, 
smooth, colorless, with thin or slightly thickened walls (up to 0.5 μm). Clamps absent.
  Known distribution: Iriomote Island (Okinawa, Japan).
  Habitat: Solitary to scattered, on ground in broad-leaved forests (dominated by Quercus 
miyagii Koidz. and Castanopsis cuspidata (Thunb.) Schottky var. sieboldii (Mak.) Nakai).
   Specimens examined: KPM-NC0010099 (holotype), Outomi (Iriomote Island), Taketomi-
cho, Okinawa-ken, May 31, 2002, coll. H.Takahashi. 
   Japanese name: Sumire-nigaiguchi. 
   Notes: This species is characterized by its medium to large, dark purple basidiomata, the 
white, bitter, unchanging flesh, the often finely purplish-reticulate stipe, the relatively small 
basidiospores, the hymeniform stipitipellis consisting of brownish, broadly clavate 
caulocystidia, and the habitat in Quercus-Castanopsis forests.
  Its white, unchanging flesh and its white then pinkish pores suggest that this species 
belongs in the section Tylopilus of the genus Tylopilus as defined by Singer (1986). Within 
this section, North American Tylopilus plumbeoviolaceus (Snell & E. A. Dick) Singer 
(Bessette et al. 2000; Singer 1947; Snell 1936; Snell and Dick 1941, 1970; Wolfe 1986) and 
Tylopilus neofelleus Hongo, originally described from Japan (Hongo 1967), are similar to T.
obscureviolaceus. The North American taxon differs in having a pileus colored more 
brownish or grayish when mature, much longer basidiospores (7-11 μm: Snell and Dick 
1941), and hymeniform pileipellis composed of fusoid-ventricose to narrowly fusoid-
ventricose pilocystidia (Wolfe 1986). Tylopilus neofelleus is distinct in forming a olive-brown 
to avellaneous pileus and purplish pores from the first.
 
  Color notations in parentheses are taken from Kornerup and Wanscher (1978).


Fig. 2. Tylopilus obscureviolaceus. 
A Basidiospores. B Cheilocystidia. C Pleurocystidia. D Elements of the pileipellis. 
All figures from the holotype. Bars 10 μm


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