Dimerella kawanae (Lichenized Ascomycota, Gyalectaceae) sp. nov. from Chiba-ken, Central Japan

Abstract

Dimerella kawanae Harada & VWzda is described as new from Chiba-ken, central Japan. It occurs on trunks of deciduous hardwoods. The lichen genus Dimerella, in the Gyalectaceae, is represented by about 50 species (Lettau 1937, as Microphilae; Santesson 1952; Vz V~zda 1969; Yoshimura & Kurokawa 1973): D. epiphylla (Muell. Arg.) Trev., D. lutea (Dicks.) Trev., D. pineti (Ach.) V~zda, and D. wrightii V~zda. Recently, another species was collected by the first author during a field survey in Sodegaura-shi, as a part of floristic work in Chiba-ken, central Japan. The same species was collected later by Mr. T. Kawana, an amature botanist in Chiba-ken and given to the first author for examination. Careful examination has revealed that these specimens belong to an undescribed species of Dimerella. MATERIALS AND METHODS Description of external morphology is based on airdried material observed under a dissecting stereoscope. Sections were made with a razor blade under a dissecting stereoscope, mounted in lactophenol cotton-blue (LPCB), and used for anatomical description, except for the color description which was based on the GAW (glycerol:ethanol: water = 1:1:1) preparations. For observing ascus, spores, paraphyses, conidia, and conidiophores in more detail, sections of apothecia or pycnidia were mounted in 10% aqueous solution of KOH, squashed gently, and the mounting medium replaced by water, ethanol, and finally LPCB. These LPCB preparations were used for the line drawings. The K, I, KI tests were conducted on sections of apothecia by using 10% aqueous solution of KOH and/ or a diluted Lugol's solution. Specimens used in this study are deposited in the herbarium of Natural History Museum and Institute, Chiba (CBM). DIMERELLA KAWANAE Harada & V~zda sp. nov. (FIGs. 1-10) Thallus crustaceus, epiphloeodicus, continuus, cinerascens viridis. Apothecia gyalectoidea, 0.25-0.50 mm lata, sessilia, constricta ad basi; discus fere planus, brunneololuteus, madefactus semipellucidus, epruinosus; margo distinctus, albidus, dilute dentatus. Sporae 2-cellulae, 10-14 x 4-5 pm. Pycnidia verruciformia in thallo immersa; conidia bacilliformia, 5-8 x 2-3 pLm, hyalina, simplicia. TYPE: JAPAN. HONSHU. Chiba-ken, Sodegaura-shi, Shimo-nitta, 30 m elev., on trunk of Salix chaenomeloides, 24 Sept. 1996, Kawana 96092401 (cBM-FL-8051, holotype); Sodegaura-shi, Uchikoshi, 20 m elev., on trunk of Aphananthe aspera at sunny site around Kumano Shrine by paddy field, Harada 15958 (cBM-FL-6942, paratype). External morphology.-Thallus crustose, epiphloeodal, continuous, 2-3 cm diam., smooth, somewhat pale greenish gray, somewhat glossy; hypothallus indistinct, whitish, thin to filmy. Apothecia gyalectoid, 0.25-0.50 mm diam., sessile, constricted at base; disc concave when young, almost flat when mature, sometimes convex, pale yellowish brown, epruinose; margin whitish (? concolorous with thallus), covering disc leaving pit when juvenile, usually whitish, ? scabrose when mature, sometimes almost dentate. Pycnidia immersed in ?0.2 mm diam., thallusdominated verruca, scattered. Anatomy.-Thallus up to 50 psm thick, ? with hyaline epinecral layer (5-10 psm thick), lacking cortex, composed of Trentepohlia-phycobiont cells and more or less filamentous hyphae. Hypothecium 10-15 lJm thick, hyaline, highly gelatinized, with variously orientated hyphae. Proper exciple cupular, usually thicker and up to 25 psm thick in uppermost part, 10-15 psm thick at base, hyaline throughout, prosoplectenchymatous, at base in distal parts merging with thallus and containing scattered phycobiont cells; hyphae radiating at sides, horizontally oriented at base, with + 1 lJm wide lumina at sides, 2-4 psm wide lumina for the outermost parts, with ?2 psm wide lumina at base. Subhymenium 15-20 pCm thick, hyaline. Hymenium 50-60 psm tall, I+ faint blue changing to + reddish, KI+ light blue (ascus only), K-; paraphyses simple, sparsely branched and anastomosing, septate, with ca 1 jim wide lumina, with spheric apical cells (lumina 2-3 jm wide). Asci clavate, 45-55 x ca 5 Cjm, lacking apical thickening, with amyloid gelatinous covering. Spores fusiform to ellipsoid, bicellular, hyaline, 10-14 x 4-5 jim, usually not constricted at sep0007-2745/97/454-457$0.55/0 This content downloaded from 207.46.13.124 on Wed, 22 Jun 2016 05:42:58 UTC All use subject to http://about.jstor.org/terms 1997] HARADA & VtZDA: DIMERELLA KAWANAE SP. NOV. 455