ヌメリイロガワリ

Boletus viscidipellis Har. Takah., Degawa & Taneyama, Mycoscience Volume 54:458-468, 2013

Etymology: from Latin, viscidi = viscid ＋pellis = pileipellis, referring to the viscid pileus surface.

傘表面は小豆色～暗赤褐色で、湿時強い粘性を帯びますが、乾燥するとほとんど粘性はなくなり、毛羽立って見える特徴があります。孔口は時に部分的に赤色を帯びることがあります。肉は強い青変性があり、柄の表面は少なくとも上半分に繊細な網目模様を形成します。 発生はまれです。

肉眼的特徴

傘は径 50-90 mm, 最初半球形のち平たい饅頭形になり, 縁部は全縁で通常僅かに突出

する; 表面は微毛に被われ, 湿時著しく粘性を帯び, 全体に赤褐色～紫褐色を呈し, 傷を受け

ても青変しない.

肉は厚さ10 mm以下, 硬くしまり, 淡黄色, しばしば柄の下部においては赤色を帯び, 空気に

触れると即座に濃く青変する; 特別な味や匂いはない.

柄は 40-60 × 15-25 mm, ほぼ円柱形または根元に向かってやや太くなる, 中心生, 中実;

表面は粘性を欠き, 最初全体に黄色を呈し, のちしばしば基部の周囲において暗赤色を帯び,

一般に全体に繊細な網目模様を表すが時に下半部に向かって不明瞭になり, 傷を受けた部分

は即座に濃青色に変わる; 根元の綿毛状菌糸体は汚白色.

管孔は柄の周囲で急激に浅く嵌入し, 長さ 8mm以下, 最初黄色, のち緑黄色; 孔口は類円

形, 微細 (通常 0.5 mm以下), 管孔よりやや濃色または時に柄の周囲において部分的に暗赤

色を帯び, 管孔及び孔口は傷を受けると即座に濃く青変する.

顕微鏡的特徴

担子胞子は 8-9.5 × 3.5-4.5 μm, 片側の下部に不明瞭ななだらかな凹み(胞子盤)を形成

し, 紡錘状楕円形, 鈍頭, 平滑, 灰黄色, 非アミロイドまたは稀に弱偽アミロイド, 僅かに厚壁 (0.

5μm).

担子器は 24-27 × 8-9.5 μm, こん棒形, 一般に2-3-4 胞子性.

縁シスチジアは 20-37 × 5-8 μm (n = 40), 群生して不実帯をなし, 狭紡錘形～頂部が細

長く伸びた片脹れ状, 平坦, 鈍頭, 無色または赤色～帯褐赤色の色素が細胞間に存在し, 非ア

ミロイド, 薄壁.

側シスチジアは 25-40 × 5-8 μm (n = 40), 散生または断続的に束生し, 縁シスチジアに

類似するが細胞間色素を欠く.

子実層托実質はイグチ亜型; 菌糸は幅 4.5-7.5 μm, 円柱形, ゼラチン化し, 側層において

無色, 中層において淡黄褐色, 平滑, 非アミロイド, 薄壁.

傘表皮の最外層は緩く錯綜し, やや圧着し, ゼラチン化する; 菌糸は幅 4-8 μm, 円柱形,

平滑, 暗緑色の凝固した内容物を有し, 薄壁.

傘表皮の内層を構成する菌糸は幅 3-10 μm, 円柱形, 緩く錯綜し, ゼラチン化せず, 帯褐

赤色～紫赤色の色素が液胞内に存在し, 平滑, 薄壁.

傘実質の菌糸は不規則に錯綜し, 幅 3-12 μm, 無色, 平滑, 薄壁.

柄の上表皮層は子実層状被をなし, 亜こん棒形～こん棒形の偽担子器型細胞および柄シ

スチジアが表皮全体を被う; 柄シスチジアは 25-48 × 10-16 μm, 広こん棒形または狭紡錘

形～頂部が細長く伸びた片脹れ状, 淡黄色または濃赤色, 平滑.

全ての菌糸はクランプを欠く.

生態: コナラ, クヌギ, スダジイなど主にブナ科の樹木からなる広葉樹林内地上に孤生～散

生, 標高60-590 m, 7月～9月.

分布: 日本 (東京, 神奈川).

主な形態的特徴:

１）傘は湿時著しい粘性を帯び, 微毛に被われる.

2) 柄は通常全体に表面と同色の繊細な網目模様を表し, 全体に黄色または時に基部の周囲

において濃赤色を帯びる.

3) 肉は空気に触れると即座に濃く青変する.

4) 孔口は管孔よりやや濃色または部分的に暗赤色を帯びる.

5) 柄シスチジアは広こん棒形または狭紡錘形～頂部が細長く伸びた片脹れ状.

所属位置並びに近縁種

ヤマドリタケ型の子実体を形成し, 管孔内部と色が異なる微細な孔口を持つ特徴は, 本種

がウラベニイロガワリ節 (Section Luridi Fr. sensu Singer 1986)に属することを示唆している.

ヌメリイロガワリの子実体の肉眼的並びに顕微鏡な特徴はアカアミアシイグチ Boletus

pseudoluridus Hongo (Hongo 1985) と多くの点で共通するが, 傘の表面が微毛に被われ且つ明

らかな粘性があること, 孔口は管孔より濃色でしばしば部分的に赤色を帯びること, 網目模様

が黄色を呈する (アカアミアシイグチの網目は赤色を帯びる)などの点で後者と区別できる. ま

た本種の子実体の外観はミヤマイロガワリの1変種北米産 Boletus sensibilis var. subviscidus

A.H. Sm. & Thiers (Smith and Thiers 1971)にも類似する. しかし北米産の標本は傘が平滑で,

柄の表面に明瞭な網目模様を欠き, 孔口は管孔と同色で, 担子胞子はより長形 (9-12 μm

long: Smith and Thiers 1971)と言われている.

Macromorphological features:

　 Pileus 50-90 mm in diam, at first hemispherical, expanding to broadly convex, with mostly

slightly appendiculate, straight margin; surface covered overall with appressed, minute, soft

hairs, sometimes glabrescent in aged specimens, smooth, viscid to subglutinous when wet,

brownish red (10D7-8) to violet brown (10E7-8) or brownish violet (11D7-8) to violet brown

(11E7-8) overall, unchanging when bruised. Flesh (Fig. 31) up to 10 mm thick at the center

of the pileus, becoming very thin toward the margin, firm, yellowish white (3A2) to pale

yellow (3A3), at times stained greyish red (10C5) to brownish red (10C6) at the base of

stipe, instantly and strongly changing to dark blue when cut; odor and taste indistinct. Stipe

40-60 × 15-25 mm, subcylindrical, often slightly thickened toward the base, central, terete,

solid; surface dry, at first entirely yellow (2A6-7 to 3A6-7) to greyish yellow (3B6-7), then

sometimes stained dark red (10C7-8) at the base, finely reticulate overall or at least over

the upper half by a thin-veined, concolorous reticulum, instantly changing to dark blue

where handled; basal mycelium whitish to sordid gray. Tubes up to 8 mm deep, shallowly

depressed around the stipe, light yellow (2A5) to yellow (2A6) at first, becoming greenish

yellow (2B6-7) with age, instantly changing to dark blue when exposed; pores 2-3 per mm,

subcircular, uniformly greenish yellow (1A6-7) to yellow (2A6), occasionally discolored red

(10B7) to brownish red (10C6-7) only near the stipe, instantly changing to dark blue when

bruised. Spore print not obtained.

Micromorphological features:

Basidiospores (Fig. 36) (8.2-) 9.4-10.6 (-11.3) × (3.4-) 3.9-4.4 (-4.7) μm (n = 128, mean

length = 10.00 ± 0.56 μm, mean width = 4.13 ± 0.26 μm, Q = (1.9-) 2.3-2.6 (-2.8), mean

Q = 2.43 ± 0.17), inequilateral with a shallow suprahilar depression in profile, fusoid-ellipsoid

in face view, with a rounded apex, smooth, with yellowish grey (2B2) contents in water,

greyish yellow (4B4) in KOH, inamyloid or rarely weakly dextrinoid, with slightly thickened

walls (up to 0.5 μm). Basidia (Fig. 35) (20.6-) 24.6-30.2 (-33.3) × (7.5-) 8.9-10.2 (-11.2) μ

m, 2-, 3-, 4-spored; sterigmata (3.6-) 3.8-5.3 (-6.2) × (1.2-) 1.3-1.7 (-1.8) μm. Basidioles

clavate. Cheilocystidia (Fig. 33) abundant, forming a compact sterile edge, (17.7-) 20.5-30.2

(-37.7) × (4.2-) 5.2-7.1 (-7.9) μm (n = 54, mean length = 25.37 ± 4.84 μm, mean width =

6.13 ± 0.94 μm), narrowly fusoid-ventricose to ventricose-rostrate with an obtuse apex,

smooth, hyaline or with intercellular red (10B7) to brownish red (10C6-7) pigments in water,

hyaline in KOH, inamyloid, thin-walled. Pleurocystidia (Fig. 34) scattered to intermittently

clustered, (28.3-) 31.4-41.4 (-45.7) × (5.7-) 6.4-8.6 (-11.8) μm (n = 44, mean length = 36.

41 ± 5.02 μm, mean width = 7.43 ± 1.07 μm), similar in shape to cheilocystidia but

entirely colorless. Hymenophoral trama bilateral-divergent of the Boletus-subtype;

constituent elements (5.0-) 6.1-8.6 (-10.4) ?m wide in lateral strata, (2.7-) 3.5-4.7 (-5.8) μ

m wide in a mediostratum, cylindrical, smooth, colorless, hyaline in KOH, inamyloid.

Outermost layer of pileipellis (Fig. 32) consisting of loosely arranged, somewhat appressed,

gelatinized elements; constituent hyphae (2.9-) 3.6-5.1 (-6.3) ?m wide, cylindrical, often with

gelatinized and roughened walls, with dark green (29F8-7) to deep green (29E8-29D8)

coagulate content in water, thin-walled; terminal cells (23.4-) 36.6-85.0 (-120.5) × (3.6-) 4.0

-7.8 (-14.1) μm (n = 37, mean length = 60.82 ± 24.23 μm, mean width = 5.87 ± 1.91 μ

m), subcylindrical, yellowish in KOH, inamyloid, thin-walled. Innermost layer of pileipellis well

differentiated from the upper stratum, made up of loosely entangled elements 3-10 ?m wide,

cylindrical, not gelatinized, with greyish red (10D4-5) to brownish red (10D6) to violet brown

(10E7-8) vacuolar pigment in water, smooth, yellowish in KOH, inamyloid, thin- walled.

Pileitrama of cylindrical, loosely interwoven hyphae (3.0-) 4.7-9.0 (-12.4) μm wide, smooth,

colorless in water, yellowish in KOH, inamyloid, thin-walled. Stipitipellis hymeniform,

composed of sterile cells (caulocystidia) and infrequent caulobasidia which envelop the

entire stipe surface; underlying stratum made up of parallel, repent hyphae 4-7.5 ?m wide,

cylindrical, smooth, colorless or light yellow (1A5) in water, thin-walled; caulocystidia on the

edges of the reticulum (Fig. 39) (29.1-) 34.8-61.9 (-83.1) × (5.7-) 7.0-10.9 (-14.8) μm (n =

55, mean length = 48.36 ± 13.59 μm, mean width = 8.95 ± 1.96 μm), subcylindrical or

narrowly fusoid-ventricose to ventricose-rostrate with an obtuse apex, smooth, with light

yellow (1A5) walls 0.5-1 μm thick, hyaline in KOH, inamyloid; caulocystidia between the

reticulum (Fig. 38) (13.9-) 16.2-24.2 (-30.5) × (7.1-) 8.0-12.4 (-20.8 ) μm (n = 35, mean

length = 20.19 ± 4.03 μm, mean with = 10.20 ± 2.24 μm), clavate, fusiform, walls 0.5-1 μ

m thick, hyaline in KOH, inamyloid; caulocystidia at the base of stipe (Fig. 40) (21.7-) 28.4-48.

6 (-69.8) × (7.0-) 9.4-14.2 (-18.3) μm (n = 52, mean length = 38.48 ± 10.12 μm, mean

width = 11.82 ± 2.38 μm), broadly clavate or narrowly fusoid-ventricose to ventricose-

rostrate with an obtuse apex, smooth, with light yellow (1A5) or dark red (10C7-8) walls 0.5-

1 μm thick, hyaline in KOH, inamyloid; caulobasidia (Fig. 37) (20.8-) 23.1-30.8 (-32.9) × (6.7

-) 7.0-9.8 (-11.2) μm, 2- to 4-spored. Stipe trama composed of longitudinally running,

cylindrical cells (3.8-) 5.3-10.4 (-16.4) μm wide, unbranched, smooth, colorless or light

yellow (1A5) in water, hyaline in KOH, dextrinoid, thin-walled. Clamp connections absent.

Habitat: Solitary to scattered, on ground in broad-leaved forests dominated by Ardisia

japonica, Castanopsis cuspidata var. sieboldii, Quercus salicina, Q. serrata, Q. acuta, and Q.

acutissima, July to September, 60-590 m alt., July to October, not common.

Known distribution: Japan (Kanagawa, Tokyo).

Specimens examined: Specimens examined: KPM-NC0008773 (holotype), Iriuda,

Odawara-shi, Kanagawa Pref., on ground in broad-leaved forest dominated by Ar. japonica,

C. cuspidata var. sieboldii, Q. salicina, and Q. acuta, 60-70 m alt., 8 Sep 2001, coll. Takahashi,

H.; KPM-NC0008738, the same place, 8 Sep 2001, coll. Takahashi, H.; KPM-NC0008741, the

same place, 8 Sep 2001, coll. Degawa, Y.; TUAT 200, Mt. Takao, Hachiouji-shi, Tokyo, on

ground in Q. serrata and Q. acutissima forest, 590 m alt., 2 Aug 1983, coll. Takahashi, H.;

TUAT 201, the same place, 5 Aug 1983, coll. Takahashi, H.; TUAT 213, the same place, 4 Sep

1983, coll. Takahashi, H.; TUAT 460, the same place, 22 Jul 1985, coll. Takahashi, H.; TUAT

506, the same place, 24 Aug 1985, coll. Matsui, H. & Takahashi, H.; KPM-NC0018049,

Nijyuisseiki no mori, Minamiashigara-shi, Kanagawa Pref., on ground in broad-leaved forest

dominated by Q. acutissima, 450 m alt, 7 Jul 2012, coll. Orihara, T. & Yamamoto, K.

Japanese name: Numeri-irogawari.

Comments: The diagnostic features of this species are the viscid, brownish red to violet

brown pileus covered overall with appressed, minute, soft hairs, the finely reticulate, light

yellow to greenish yellow stipe occasionally stained dark red at the base, the intensely

cyanescent flesh, the occasionally discolorous (red) pores only near the stipe, the broadly

clavate or narrowly fusoid-ventricose to ventricose-rostrate caulocystidia, and the habitat

in deciduous oak forests. Although this species seems to have some intermediate

characters of the section Luridi and the section Appendiculati, we prefer to place it in the

former section because the pores occasionally become discolored red near the stipe, the

character not known in the latter section.

Boletus viscidipellis is somewhat similar to Japanese B. pseudoluridus Hongo (Hongo 1985) in

appearance, though it can be distinguished from the latter by having the viscid to

subglutinous, hairy pileus, the occasionally discolorous (red) pores, and the yellow reticulum

in the stipe. Boletus sensibilis var. subviscidus A.H. Sm. & Thiers from North America (Smith

and Thiers 1971) also has some macromorphological similarities to B. viscidipellis, however it

does not correspond to the present species due to a consistently glabrous pileus, lack of

conspicuous reticulations on the stipe surface, and not discolorous, yellow pores.

References

Hongo T (1985) Notes on Japanese larger fungi (23). J Jpn Bot 60:370-378

Singer R (1986) The Agaricales in modern taxonomy, 4th edn. Koeltz, Koenigstein

Smith AH, Thiers HD (1971) The boletes of Michigan. The University of Michigan Press,

Ann Arbor　

Takahashi, H.; Taneyama, Y.; Degawa, Y. (2013). Notes on the boletes of Japan 1. Four new species of the genus Boletus from central Honshu, Japan. Mycoscience. 54:458-468