ウロコキイロイグチ
Pulveroboletus brunneoscabrosus Har. Takah., Mycoscience 48 (2): 93 (2007)
傘と柄はレモン黄色の粉質物を帯び、橙褐色～褐色の圧着した鱗片に被われ、肉は著しくゼラチン化し、柄の表面が通常粘液に被われ、変色性を欠く性質があります。
日本の温帯低地林内などで傘が橙赤色を帯び、表面にひび割れを形成するウロコキイロイグチに似たサンプルがしばしば発生しますが、管孔に青変性を有する場合、中国の亜熱帯地域に分布する Pulveroboletus brunneopunctatus (Wu et al. 2016)に近縁かもしれません。
Immature basidioma of Pulveroboletus brunneoscabrosus (KPM-NC0013148), 6 Jun. 2004, Ishigaki Island. Photo by Takahashi, H.
柄が粘液に被われたウロコキイロイグチの幼菌 (KPM-NC0013148), 2004年6月6日, 石垣島
Mature basidioma of Pulveroboletus brunneoscabrosus (KPM-NC0013148), 6 Jun. 2004, Ishigaki Island. Photo by Takahashi, H.
ウロコキイロイグチの成熟した子実体, 2004年6月6日, 石垣島
Mature basidioma of Pulveroboletus brunneoscabrosus (KPM-NC0013148), 6 Jun. 2004, Ishigaki Island. Photo by Takahashi, H.
ウロコキイロイグチの成熟した子実体, 2004年6月6日, 石垣島
Pileus surface of Pulveroboletus brunneoscabrosus (KPM-NC0013148), 6 Jun. 2004, Ishigaki Island. Photo by Takahashi, H.
ウロコキイロイグチの傘表面, 2004年6月6日, 石垣島
肉眼的特徴 (Figs. 227–232): 傘は径20–50 mm, 最初半球形, のち饅頭形～中高偏平, 表面は全体に黄色の粉質物を帯びた橙褐色～褐色の被膜に被われ, まもなく亀甲状にひび割れ, 圧着した鱗片状をなし, 鱗片状被膜は乾性, 鱗片下部の地はレモン黄色で湿時やや粘性. 肉は厚さ4 mm 以下 (傘中央部), 淡黄色, 空気に触れても変色せず, 特別な味や臭いはない. 柄は60–100×15–25 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, 網目を欠く; 表面は湿時強い粘性があり, 頂部はレモン黄色, 下部は橙褐色の鱗片に被われる; 根元は白色綿毛状菌糸体に被われる. 内被膜は綿毛状膜質, レモン黄色の粉質物を帯び, まれに微かな繊維状のツバを形成する. 管孔は長さ6 mm 以下, 柄の周囲においてやや嵌入し, 最初黄色, 成熟すると帯褐黄色になり, 変色性を欠く; 孔口は小型 (2–3 per mm), 管孔と同色, 傷を受けても変色しない.
顕微鏡的特徴 (Fig. 226): 担子胞子は7–10 × 4–5 μm (n = 38, Q = 1.75–2.0), 広楕円形、下部側面に不明瞭でなだらかな凹みがあり(イグチ型), 平坦, 蜜色 (水封), 厚壁. 担子器は25–35 × 6–10 μm, こん棒形, ４胞子性. 縁シスチジアは25–40 × 5–8 μm, 幅の狭い紡錘形～亜紡錘形, 平滑, 無色 (水封), 薄壁. 側シスチジアは散在し, 35–52 × 6–10 μm, 形状は縁シスチジアに類似する. 子実層托実質の菌糸は幅3–7 μm, 並列し, 円柱形, 著しくゼラチン化し, 平滑, 淡黄色 (水封), 薄壁. 傘表面はゼラチン化した平行菌糸被; 菌糸は幅2.5–6 μm, 円柱形, 錯綜し, 淡褐色の色素が細胞内に存在し (水封), 細胞間に黄色の粒状物が散在し, 薄壁. 傘実質の菌糸は幅2.5–15 μm, 緩く錯綜し, 円柱形, 著しくゼラチン化し, 平滑, 無色 (水封), 薄壁. 柄表皮組織の菌糸は幅2.5–7 μm, 円柱形, 匍匐性, 錯綜し, 著しくゼラチン化し, 平滑, 淡褐色の色素が細胞内に存在し (水封), 細胞間に黄色の粒状物が散在し, 薄壁. 柄実質の菌糸は幅3–8 μm, 縦に沿って配列し, 円柱形, 時折分岐し, 著しくゼラチン化し, 平滑, 無色 (水封), 薄壁. 全ての組織において菌糸はクランプを欠く.
生態および発生時期: スダジイ, オキナワウラジロガシを主体とする亜熱帯性常緑広葉樹林内およびイチイガシを主体とする暖温帯性常緑広葉樹林内地上に孤生または散生, 5月～9月.
分布: 沖縄 (石垣島), 鹿児島 (奄美大島), 宮崎.
供試標本: KPM-NC0010098 (正基準標本), スダジイ，オキナワウラジロガシを主体とする亜熱帯性常緑広葉樹林内地上, 沖縄県石垣市バンナ公園, 2002年5月30日, 高橋春樹採集; KPM-NC0013148, 同上, 2004年6月6日, 高橋春樹採集; KPM-NC0013147, スダジイ，オキナワウラジロガシを主体とする亜熱帯性常緑広葉樹林内地上, 沖縄県石垣市オモト岳, 2003年5月25日, 高橋春樹採集; KPM-NC0013155, イチイガシを主体とする暖温帯性常緑広葉樹林内地上, 宮崎県高原町, 2001年9月21日, 黒木秀一採集; KPM-NC0013156, 亜熱帯性常緑広葉樹林内地上, 鹿児島奄美大島宇検村, 2002年9月22日, 波多野英治採集.
主な特徴: 傘と柄はレモン黄色の粉質物を帯び, 橙褐色～褐色の圧着した鱗片に被われ, 柄の表面は一般に粘液に被われる; ツバは消失性, 綿毛状膜質, レモン黄色の粉質物を帯びる; 肉は著しくゼラチン化し, 変色性を欠く; 亜熱帯～温帯の常緑広葉樹林内地上に発生.
コメント: 北米から新種記載されたキイロイグチ Pulveroboletus ravenelii (Berk. & M.A. Curtis) Murrill (Berkeley and Curtis 1853; Singer 1947; Snell and Dick 1970; Smith and Thiers 1971; Corner 1972; Grund and Harrison 1976; Nagasawa 1989; Bessette et al. 2000) 並びにマレーシア産 Pulveroboletus frians Corner (Corner, 1972) は本種に最も類似した特徴を持つが, 両種とも橙褐色の鱗片を欠き, 肉は青変性を有する. 本種はまたアフリカ (コンゴ) 産 Pulveroboletus aberrans Heinem. & Gooss.-Font. (Heinemann, 1951, 1954) にもやや似るが, アフリカ産種は傘と柄の表面が全体に橙褐色を帯びた密綿毛状を呈し, 肉は青変する.
生態および発生時期: スダジイ, オキナワウラジロガシを主体とする亜熱帯性常緑広葉樹林内およびイチイガシを主体とする暖温帯性常緑広葉樹林内地上に孤生または散生, 5月～9月.
分布: 沖縄 (石垣島), 鹿児島 (奄美大島), 宮崎.
Pulveroboletus brunneoscabrosus Har. Takah.ウロコキイロイグチ
Mycoscience 48 (2): 93 (2007) [MB#529990].
Etymology: The specific epithet means “brunneo- (brown-) + scabrosus (scabrous)”, referring to the brownish-orange, appressed scales.
Macromorphological characteristics (Figs. 227–232): Pileus 20–50 mm in diameter, at first hemispherical, expanding to convex to broadly convex; surface wholly yellow (2A6–7 to 3A6–7) pulverulent, subviscid when wet, at first covered overall with an orange (6B7) to brownish-orange (6C7–8) veil that soon breaks up into appressed scales, ground color lemon-yellow (under scales), unchanging when bruised. Flesh up to 4 mm thick, light yellow, strongly fleshy-gelatinous, unchanging when cut; odor and taste indistinct. Stipe 60–100 × 15–25 mm, subequal or somewhat enlarged toward the base, central, terete, solid, non-reticulate; surface entirely yellow (2A6–7 to 3A6–7) pulverulent, viscid to subglutinous when wet, lemon-yellow, sheathed with orange (6B7) to brownish-orange (6C7–8), appressed scales at least over the lower part, unchanging when bruised; base covered with whitish mycelial tomentum. Partial veil yellow pulverulent, floccose-membranous to floccose-fibrillose, rarely leaving a faint fibrillose annulus. Tubes up to 6 mm deep, slightly depressed around the stipe, at first light yellow, then brown (6B7) at maturity, unchanging; pores small (2–3 per mm), subcircular, concolorous with the tubes, unchanging when bruised.
Micromorphological characteristics (Fig. 226): Basidiospores 7–10 × 4–5 μm (n = 38, Q = 1.75–2.0), inequilateral with a shallow suprahilar depression in profile, broadly ellipsoid in face view, smooth, melleous in water, thick-walled (up to 1 μm). Basidia 25–35 × 6–10 μm, clavate, four-spored. Cheilocystidia 25–40 × 5–8 μm, subfusoid to narrowly fusoid-ventricose, colorless in water, thin-walled. Pleurocystidia scattered, similar in shape to the cheilocystidia but larger (35–52 × 6–10 μm). Hyphae of hymenophoral trama 3–7 μm wide, cylindrical, parallel to each other, strongly gelatinized, smooth, pale yellow in water, thin-walled. Pileipellis consisting of repent, appressed, interwoven, gelatinized hyphal elements; constituent hyphae 2.5–6 μm wide, parallel, cylindrical, with intracellular brownish (in water) pigment, with intercellular yellow granular matter, thin-walled. Pileitrama of cylindrical, loosely interwoven hyphae 2.5–15 μm wide, strongly gelatinized, smooth, colorless in water, thin-walled. Stipitipellis composed of repent, appressed, interwoven, gelatinized hyphal elements; constituent hyphae 2.5–7 μm wide, cylindrical, with intracellular brownish (in water) pigment, with intercellular yellow (in water) granular matter, thin-walled. Stipe trama composed of longitudinally arranged, cylindrical hyphae 3–8 μm wide, occasionally branched, strongly gelatinized, smooth, colorless in water, thin-walled. Clamps absent in all tissues.
Habitat and phenology: Solitary to scattered on ground in subtropical evergreen broad-leaved forests dominated by Quercus miyagii Koidz. and Castanopsis sieboldii (Makino) Hatus. ex T. Yamaz. et Mashiba, or warm temperate evergreen broad-leaved forests dominated by Q. gilva Blume, May to September.
Known distribution: Okinawa (Ishigaki Island), Kagoshima (Amami-Oshima Island), Miyazaki.
Specimens examined: KPM-NC0010098 (holotype), on ground in a subtropical evergreen broad-leaved forest dominated by Q. miyagii and C. sieboldii, Banna Park, Ishigaki-shi, Okinawa Pref., 30 May 2002, coll. Takahashi, H.; KPM-NC0013148, same place, 6 Jun. 2004, coll. Takahashi, H.; KPM-NC0013147, on ground in a subtropical evergreen broad-leaved forest dominated by Q. miyagii and C. sieboldii, Omoto-dake, Ishigaki-shi, Okinawa Pref., 25 May 2003, coll. Takahashi, H.; KPM-NC0013155, on ground in an evergreen broad-leaved forest dominated by Q. gilva, Takaharu-cho, Miyazaki Pref., 21 Sep. 2001, coll. Kurogi, S.; KPM-NC0013156, on ground in a subtropical evergreen broad-leaved forest, Uken-son, Amami-Oshima Island, Kagoshima Pref., 22 Sep. 2002, coll. Hadano, E.
Japanese name: Uroko-kiiroiguchi.
Comments: This species is characterized by the lemon-yellow pulverulent, viscid pileus and stipe covered overall with orange to brownish-orange, appressed scales; the yellow pulverulent, floccose-membranous to floccose-fibrillose, soon collapsing annulus; the non-cyanescent (unchanging), strongly fleshy-gelatinous flesh; and the habitat in subtropical and warm temperate evergreen broad-leaved forests.
Pulveroboletus brunneoscabrosus is most similar in appearance to Pulveroboletus ravenelii (Berk. & M.A. Curtis) Murrill, originally described from North America (Berkeley and Curtis 1853; Singer 1947; Snell and Dick 1970; Smith and Thiers 1971; Corner 1972; Grund and Harrison 1976; Nagasawa 1989; Bessette et al. 2000), and Malaysian Pulveroboletus frians Corner (Corner 1972). The latter two taxa, however, differs from the present species in lacking brownish-orange, appressed scales on the pileus and stipe surfaces, and forming cyanescent flesh. Pulveroboletus aberrans Heinem. & Gooss.-Font. from Congo (Heinemann 1951, 1954) also bears some resemblance to P. brunneoscabrosus, but the former is distinct in an entirely orange-brown tomentose pileus and stipe, and has cyanescent flesh.
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