肉眼的特徴: 傘は径5-8(-12) mm, 最初半球形～饅頭形で縁部は内側に巻き, のちほぼ平開し, 時に中央部が凹み, しばしば橙褐色～黒褐色の中丘を具える; 表面は乾性, 全体に縁部に向かって放射状に走る帯褐橙色～褐色の毛に被われ, しばしば同心円状の環紋を表す. 肉は非常に薄く (0.5 mm以下), 白色, 特別な味や臭いはない. 柄は8-15(-20) × 0.7-1.3 mm, ほぼ上下同大または基部がやや拡大し, 中心生, やせ型, 中空, 全体に帯褐橙色～褐色の毛に被われ, 根元に発達した菌糸体は見られない. 根状菌糸束は5-15(-30) × 0.02-0.6 mm, 糸状, 強靱, 白色, 無分岐, 空中に向かって伸長し, 基質上に散生し, 子実体から独立して形成される. ヒダは上生, 柄に到達するヒダは19-23, 1-3の小ヒダを交え, 幅 1.5 mm以下, 白色, 老成時は淡褐色を帯びる; 縁部は細縁毛があり, 同色. 　

  顕微鏡的特徴: 担子胞子は(9.5-)11-13 × (4-)4.5-5 μm, 長楕円形, 平坦, 無色, 非アミロイド, 稀に隔壁を有し, 薄壁. 担子器は25-27 × 3-8 μm, こん棒形, ４胞子性; 偽担子器は紡錘形または亜こん棒形. 縁シスチジアは17-33 × 6-10 μm, 群生し, 縁部に不稔帯を成し, 子実層から突出し, 亜こん棒形, 2-3個の短指状頂生付属糸 (1-5 × 1-2.5 μm) を持ち, 平坦, 無色, 非アミロイド, KOHにより無色, 薄壁. 側シスチジアはない. 子実層托実質の菌糸は径3-8 μm, 平列し, 亜円柱形, 膨大せず, 平坦, 無色, 非アミロイド, KOHによる反応は陰性, 薄壁. 傘の表皮は毛状細胞に接続する類円柱形の菌糸細胞(径5-7 μm)が層をなし, 無色で厚さ1-2 μmの細胞壁を持ち, 非アミロイドまたは弱偽アミロイド; 傘の毛状細胞は400-600 × 4-6 μm, 匍匐性または直立し, 円柱形, 頂部は鈍頭, 時に屈曲し, 帯褐橙色で厚さ1-2 μmの細胞壁を有し, 強偽アミロイドに染まり, KOHによりオリ－ブ緑色に変わり, しばしば複数の二次隔壁が梯子状構造を形成する. 傘実質の菌糸は径5-10 μm, 子実層托実質の菌糸に類似する. 柄の毛状細胞は傘と同様. 柄の実質は縦に沿って配列した円柱形の菌糸(径5-13 μm) からなり, 無色, 非アミロイド, KOHによる反応は陰性. 根状菌糸束の菌糸は径2-5 μm, 子実体の毛状細胞に類似し, 頂部に向かって次第に細まり, 密集し, 並列し, 頂部は鈍頭, 厚壁(厚さ0.5-2 μm), 非アミロイドの頂部以外は偽アミロイドに染まり, KOHによる反応は陰性または淡オリ－ブ緑色に変わり, 頂部付近においてしばしば二次隔壁が存在する. 全ての組織において菌糸にクランプが見られる.   

  供試標本: KPM-NC0017526, 沖縄県石垣市バンナ岳, 枯れ枝上, 2010年7月25日, 採集者: 高橋春樹, 寺嶋芳江; KPM-NC0017297 (holotype), Banna-dake, Ishigaki-shi, Okinawa pref., on dead fallen twigs, 3 July 2006, coll. Takahashi, H.; KPM-NC0017298, same place, 13 Jun. 2006, coll. Takahashi, H.; KPM-NC0017299, same place, 15 Jun. 2007, coll. Takahashi, H.; KPM-NC0017527, same place, 11 Aug. 2010, coll. Takahashi, H.

    主な形態的特徴

1) 本種の子実体はアルカリ溶液 (5%KOH またはNaOH)によりオリ－ブ緑色に変わる毛状細胞が傘と柄の表皮に存在する.

2) 担子胞子はやや長形で, 長さ11-13 μmに達する.

3) 2-3個の短指状頂生付属糸を具えた縁シスチジアが存在し, 側シスチジアを欠く.

4) 基質(枯れ枝)上に子実体の毛状細胞と共通する形態的性質を持つ白色紐状菌糸束が散生する.  

   コメント: KOHによりオリ－ブ緑色に変わる毛状細胞を有する性質に基づき, 本種はSinger (1976, 1986) の分類概念による Crinipellis sect.Grisentinae (Singer) Singerに属すると考えられる. 

Grisentinae 節において本種は以下の4種と肉眼的類似性が見られる. 

1) ブラジル産 (Singer 1976) Crinipellis sapindacearum Singer. 

2) Singer (1976)の記載による新熱帯産Crinipellis trichialis (Lev.) Pat. ex Antonin R. Ryoo & H.D. Shin. 

3) アルゼンチン産(Singer 1976)Crinipellis tucumanensis Singer. 

4) 韓国産(Antonin et al. 2009) Crinipellis rhizomaticola Antonin. 

  これら4種は主に発達した側シスチジアを有し, より短形の担子胞子を持ち, 基質上に菌糸束が存在しない点で本種と区別できる. 更にCrinipellis sapindacearumはムクロジ科(Sapindaceae)の樹木の落ち葉上に発生し, Crinipellis rhizomaticola はより大型(径12-22 mm)で赤褐色の傘を形成する点で本種と異なる. マレーシア産(Corner 1996) Crinipellis nigrilineata Cornerも本種にやや類似するが, 傘はより大型で (径10-35 mm: Corner 1996)放射状の溝線を表し, 縁シスチジアおよび菌糸束を欠く.

Crinipellis rhizomorphica Har. Takah.

 Mycoscience Volume 52, Number 6, 392-400, 2011   　　　　

Macromorphological features:

  Pileus (Fig. 1) 5-8(-12) mm in diam, at first hemispherical to convex with incurved margin, then broadly convex to nearly plane, sometimes with depressed center, often with a brownish orange (6C7-8 or 7C7-8) or blackish, broad umbo at center; surface dry, radially fibrillose-squamulose with strigose, brownish orange (6C7-8 or 7C7-8) to brown (7D7-8) hairs projecting beyond the margin, often concentrically zoned, dull, opaque.　Flesh very thin (up to 0.5 mm), white, pliant but easily broken, odor and taste not distinctive.　Stipe 8-15(-20) × 0.7-1.3 mm, subequal or slightly enlarged at the base, central, slender, terete, hollow, entirely strigose-fibrillose with brownish orange (6C7-8 or 7C7-8) to brown (7D7-8) hairs, basal mycelium not seen. Lamellae adnexed, 19-23 reach the stipe, with 1-3 series of lamellulae, up to 1.5 mm broad, white; edges ciliate to fimbriate, concolorous. Rhizomorphs (Fig. 2) independent of the formation of basidiomata, growing into the air, scattered on the substratum, 5-15(-30) × 0.02-0.6 mm, thread-like, gradually tapering toward the apex, tough, not branched, dense, parallel, white, inamyloid in the apical portion but otherwise dextrinoid, hyaline or turning pale olivaceous in KOH; constituent hyphae similar to the hairs of basidiomata, 2-5 μm diam, cylindrical, with rounded apex, with smooth walls 0.5-2 μm thick, often with several secondary septa near the apical portion.　 

Micromorphological features:

  Basidiospores (Fig. 5) (9.5-)11-13 × (4-)4.5-5 μm (Q = length/breadth: 2.4-2.6), oblong-ellipsoid, smooth, colorless, inamyloid, rarely septate, thin-walled.　Basidia 25-27 × 3-8 μm, clavate, 4-spored; basidioles fusiform to subclavate. Cheilocystidia (Fig. 4) 17-33 × 6-10 μm, gregarious, forming a compact sterile edge, projecting from the hymenium, subclavate, with two or three short cylindrical apical appendages 1-5 × 1-2.5 μm, smooth, colorless, inamyloid, hyaline in KOH, thin-walled. Pleurocystidia none.　 Hyphae of hymenophoral trama 3-8 μm diam, parallel, subcylindrical, not inflated, smooth, colorless, inamyloid, hyaline in KOH, thin-walled.　Pileipellis a hypotrichial layer of subcylindrical cells 5-7 μm diam, with smooth, colorless walls 1-2 μm thick, inamyloid or weakly dextrinoid; hairs of pileus (Fig. 3) 400-600 × 4-6 μm, arising directly from the hypotrichium, repent or erect, cylindrical, with a rounded apex, sometimes flexuous, with smooth, brownish orange (6C7-8) walls 1-2 μm thick, strongly dextrinoid, turning olive yellow (3C6-8) in KOH, occasionally with several secondary septa.　Hyphae of pileitrama 5-10 μm diam, similar to those of the hymenophoral trama. Hairs of stipe similar to those of the pileus.　Stipe trama composed of longitudinally running, cylindrical hyphae 5-13 μm wide, smooth, colorless, inamyloid, hyaline in KOH, thin-walled.　Clamps present in all tissues. 

      Habitat: Solitary or scattered, on dead twigs (unidentified substrata), June to July.

Specimens examined: KPM-NC0017526, Banna-dake, Ishigaki-shi, Okinawa pref., on dead fallen twigs, 25 July 2010, coll. Takahashi, H. & Terashima,Y.; KPM-NC0017297, same place,  3 July 2006, coll. Takahashi, H.; KPM-NC0017298, same place, 13 Jun. 2006, coll. Takahashi, H.; KPM-NC0017299, same place, 15 Jun. 2007, coll. Takahashi, H.; KPM-NC0017527, same place, 11 Aug. 2010, coll. Takahashi, H.

    Known distribution: Japan (Okinawa).

    Comments:  Crinipellis rhizomorphica has the characteristics of the brownish orange, fibrillose-squamulose basidiomata accompanied by the white thread-like rhizomorphs on the dead twig, the dextrinoid hairs turning olivaceous in KOH, the oblong-ellipsoid, relatively long basidiospores averaging 12 × 4.75 μm, the subclavate cheilocystidia with two or three short cylindrical apical appendages, and the absence of pleurocystidia. Its olivaceous-colored hairs in KOH suggest that the present fungus is best accommodated in the section Grisentinae (Singer) Singer (Singer 1976, 1986).

  Within the section Grisentinae, C. rhizomorphica has macromorphological similarities to the following four species: C. sapindacearum Singer from Brazil (Singer 1976); C. trichialis (Lev.) Pat. ex Antonin R. Ryoo & H.D. Shin (Leveille 1846; Saccardo 1887; Antonin et al. 2009), redescribed by Singer from Venezuela (Singer 1976) and by Kerekes & Desjardin from Indonesia and Malaysia (Kerekes and Desjardin 2009); C. tucumanensis Singer from Argentina (Singer 1976); and C. rhizomaticola Antonin from Republic of Korea (Antonin et al. 2009). These taxa mainly differ from C. rhizomorphica in having well developed pleurocystidia and lacking rhizomorphs. Furthermore, C. sapindacearum has much smaller basidiospores: 7.5-8.2 × 3-3.5 μm (Singer 1976) and a habit on dead fallen coriaceous leaves of Sapindaceae. Crinipellis trichialis produces shorter and broader basidiospores: (8.5-) 9.6-11.5 × (5.5-)6-7(-7.4) μm (Kerekes and Desjardin 2009, Holotype: FH!). Crinipellis tucumanensis forms much shorter basidiospores: 5.5-8.5 μm long (Singer 1976). Crinipellis rhizomaticola is distinct in having a chestnut-brown, larger pileus: 12-22 mm in diam (Antonin et al. 2009) and significantly shorter basidiospores: 8.5-10 μm long (Antonin et al. 2009). Crinipellis rhizomorphica also shares characteristics such as olivaceous-colored hairs in KOH, copious rhizomorphs, and a radially fibrillose-strigose pileus with a minute blackish papilla in umbilicus in common with the following two species: Southeast Asian C. actinophora (Berk. & Broome) Singer (Berkeley and Broome 1874; Singer, 1955; Pegler, 1986; Corner 1996; Kerekes and Desjardin 2009); and C. nigricaulis Har. Takah. from Japan (Takahashi 2000) and Republic of Korea (Antonin et al. 2009). These two taxa, however, can be discerned from C. rhizomorphica by forming a dark brown stipe occasionally associating with the much longer, dark brown, 'hair-blight' rhizomorphs, significantly shorter basidiospores: 6-10 μm long (Kerekes and Desjardin 2009), and cheilocystidia with numerous apical appendages.

References  

Antonin V, Ryoo R, Shin H-D (2009) Marasmioid and gymnopoid fungi of the Republic of Korea. 1. Three interesting species of Crinipellis (Basidiomycota, Marasmiaceae). Mycotaxon 108:429-440

Berkeley MJ, Broome CE (1874) Enumeration of the fungi of Ceylon. Part II. Journ Linn Soc Bot 14:29-141

Corner EJH (1996) The agaric genera Marasmius, Chaetocalathus, Crinipellis,

  Heimiomyces, Resupinatus, Xerula, and Xerulina in Malesia. Beiheft Nova Hedwig

  111:1-164　  

Kerekes J, Desjardin DE (2009) A monograph of the genera Crinipellis and Moniliophthora from Southeast Asia including a molecular phylogeny of the nrITS region. Fungal Diversity 37:101-152

Leveille JH (1846) Descriptions des champignons de l'herbier du Museum de Paris. Annls Sci Nat, Bot, ser 3 5:111-167

Kornerup A, Wanscher JH (1983) Methuen handbook of colour. Eyre Methuen, London  

Pegler DN (1986) Agaric flora of Sri Lanka. Kew Bulletin Add Ser XII. HMSO, London 

Saccardo PA (1887) Sylloge Hymenomycetum, Vol. I. Agaricineae. Syll fung 5:1-1146 

Singer R (1943) A monographic studies of the genera of Crinipellis and Chaetocalathus.

  Lilloa 8:441-534 

Singer R (1976) Marasmieae (Basidiomycetes - Tricholomataceae). Flora Neotrop Monogr  17:1-347   

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

Takahashi, H. (2000). Three new species of Crinipellis found in Iriomote Island, southwestern Japan, and central Honshu, Japan. Mycoscience 41:171-182 

Takahashi H (2011) Two new species of Agaricales and a new Japanese record for 

  Chaetocalathus fragilis from Ishigaki Island, a southwestern island of Japan. Mycoscience 52: 392-400

****************************************************

 * Color notations in parentheses are taken from Kornerup and Wanscher (1983).

Specimens cited here are deposited in the Kanagawa Prefectural Museum of Natural 

History, Japan (KPM).