キヒダサカズキタケ

Hydropus aurarius Har. Takah., Mycoscience 43 (5): 399 (2002) [MB#489168] 

カヤタケ型の子実体を形成する中型種で, 暗褐色の小鱗片に被われた傘と柄からなり, 鮮黄色のヒダを持ちます。 ニセアシナガタケ属(Hydropus)は傘表皮組織がしばしば不連続な子実層状被をなし、実質は紡錘形の骨格菌糸を有する性質があります。 属内では紡錘形の骨格菌糸を持つ点で熱帯産Hydropus anthidepas 近縁種群に近いと思われます。広葉樹の材から単生～散生し, 神奈川, 宮城, 栃木に分布し、地球博物館がある小田原市入生田が基準産地です。

黄色の色素を持つ点で欧州産 Chrysomphalina chrysophylla に外観が似ていますが、キヒダサカズキタケは実質が紡錘形の骨格菌糸と原菌糸からなる (*Sarcodimitic) 点で欧州産種と異なります。

 Hydropus aurarius Har.Takah., Mycoscience (2002) 43:397-403　　

　 Pileus 20-35 mm in diameter, at first hemispherical, then convex with depressed center, usually with a dark brownish, obtuse umbo, smooth, covered overall with minute, dark brown, fibrillose-floccose particles which crowd toward the disk, yellowish under dark brown particles. Flesh up to 1.5 mm, pale yellow; odor and taste not distinctive. Stipe 50-70×4-5.5 mm, almost equal or somewhat thickened toward the base, central, slender, terete, hollow, often entirely longitudinally rugulose, dark brown furfuraceous overall on the yellowish background; base covered with conspicuous white mycelioid tomentum. Lamellae arcuate-decurrent, subdistant (35-38 reach the stipe), with 1-3 series of lamellulae, up to 2.5 mm broad, yellow (3A7-8); edges concolorous.

  Spore print pure white. Basidiospores 5-6.5×2.7-3.2 μm [Q = length/breadth: 1.8-2.0, n = 20 spores per two specimens], ellipsoid, smooth, colorless, inamyloid, thin-walled. Basidia 25-30×5-6 μm, clavate, four-spored. Cheilocystidia and pleurocystidia absent. Hymenophoral trama regular; hyphae similar to those of the pileitrama but with vivid yellow (3A8), intercellular, coagulate pigments. Pileipellis a cutis of cylindrical cells 3-8 μm wide, smooth, colorless or with yellowish brown (5E6-7 to 5F6-7) contents, thin-walled, occasionally with clamped septa; pileocystidia 20-40×4-8μm, subcylindrical, decumbent, sometimes aggregate, with yellowish brown (5E6-7 to 5F6-7), vacuolar pigments. Hyphae of pileitrama 3-25 μm wide, parallel to the pileipellis elements, sarcodimitic, intermixed with filamentous, short hyphae and very long, strongly inflated, unbranched, subfusiform hyphae, colorless, inamyloid, thin-walled, occasionally with clamped septa. Stipitipellis a cutis of parallel, repent hyphae 3-8 μm wide, cylindrical, colorless or pale yellow, inamyloid, thin-walled, occasionally with clamped septa; caulocystidia 30-50×5-7 μm, subclavate, smooth, with yellowish-brown (5E6-7 to 5F6-7), vacuolar pigments, thin-walled. Hyphae of stipe trama 5-18 μm wide, longitudinally running, sarcodimitic, very long, strongly inflated, unbranched, subfusiform to cylindrical, smooth, colorless or pale yellow, inamyloid, thin- or slightly thick-walled, occasionally with clamped septa.

  Known distribution: Japan (Kanagawa, Miyagi, Tochigi).

  Habitat: Solitary to scattered, on fallen dead twigs in lowland oak forests.

  Specimens examined: KPM-NC0006727 (holotype), Iriuda, Odawara-shi, Kanagawa-ken, July 2, 2000, coll. H.Takahashi; the same place, Aug. 21, 2000, coll. H.Takahashi; the same place, Sept. 5, 2000, coll. H.Takahashi; KPM-NC0008684, Ryuoukyo, Fujiwara-cho, Tochigi-ken, Aug. 25, 2001, coll. Y.Shibata; KPM-NC0008685, Mt.Aoba, Sendai-shi, Miyagi-ken, Aug. 5, 2001, coll. Y.Goto & Y.Ando.

  Japanese name: Kihida-sakazukitake.

  Notes: The important combination of features delimiting this species is its clitocyboid basidiomata with a dark brown furfuraceous pileus and stipe, the vivid yellow lamellae, the relatively small basidiospores, the sarcodimitic trama, and its habitat on a fallen dead twig.

  The presence of sarcodimitic tramal hyphae suggests that this species belongs in the genus “Trogia" as defined by Corner (1966). However, because of the too wide concept, I do not accept the generic circumscription of “Trogia" (sensu Corner). Its clitocyboid habit and vivid yellow lamellae has superficial resemblance to the genus Gerronema (Singer 1986) which differs in having mostly filamentous, monomitic tramal hyphae and usually lacking fuscous pigments in the terminal elements of the pileipellis and stipitipellis.

  This species seems to be allied with several neotropical taxa, viz. Hydropus citrinus Singer (Singer 1982), Hydropus xanthosarx Singer & Grinling (Singer and Grinling 1967),

Gerronema icterinum (Singer) Singer (Pegler 1983), and “Trogia” citrina Corner (Corner 1966). Hydropus citrinus and H. xanthosarx differ in forming cheilocystidia and having a

glabrous pileus and stipe. Gerronema icterinum and T. citrina primarily differ in having a glabrescent pileus and stipe colored sulphur yellow to mustard yellow. Moreover, T. citrina has two-spored basidia. Hydropus aurarius is also similar to “Trogia" straminea Corner (1966) from Singapore which differs in having pale ochraceous lamellae, much larger basidiospores, and ventricose- lanceolate pileocystidia that form palisadoderm in the pileipellis.

References

Corner EJH (1966) A monograph of cantharelloid fungi. Ann Bot Mem 2:1–255

Pegler DN (1983) Agaric flora of the Lesser Antilles. Kew Bull Addit

Ser IX. Her Majesty’s Stationery Office, London

Singer R (1982) Hydropus (Basidiomycetes-Tricolomataceae-Myceneae). Flora Neotrop Monogr 32:1–153

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

Singer R, Grinling K (1967) Some Agaricales from the Congo. Persoonia 4:355–377

Takahashi, H. 2002. Two new species and one new combination of Agaricales from Japan. Mycoscience. 43(5):397-403