Phylum：Basidiomycota　>>　Class： Ustilaginomycetes　>>　 Order： Exobasidiales 
   
 
　BCRC Number： NO BCRC Number!  
   
　Scientific Name： Exobasidium japonicum
 
   
   
　Author：

?Exobasidium formosanum Sawada, Desscript. Cat. Formosan Fungi II, p107, 1922..

Exobasidium japonicum Shirai, Bot. Mag. Tokyo 10:52, 1896..
   
 
 
 
 
　Description： Infected leaves producing one to several conspicuous, circular concaved, pouch- or ball-shape galls, pale green and turned pink occasionally. Hymenium composed of basidia, basidiospores and conidia. Basidia hyaline, cylindrical to clavate, (30-)40-116 × (4.5-)5-8(-10.7) μm, with (3-)4-6 sterigmata. Sterigmata subulate, (3-)4-6 × (1.5-)2-3 μm. Basidiospores hyaline, smooth, obovoid, banana-shape, slightly curved at the base, (12-)14-20(-24) × (2.5-)3-4(-5) μm, with 1-3(-5) septa. Conidia hyaline, filiform, fusiform, bacilliform, clavate, 5-17(-19) × 0.8-2μm. Basidiospores on PDA or water agar germinating from the both end cells with 1-2 long germ tubes and then producing conidia; but some basidiospores germinating with a short germ tube. Colonies on PSA sticky, pale yellow, wrinkled irregularly in early stage, but fragile, gel-like, mealy, dull and dry in old stage. Media culturing isolates from Rhododendron oldhamii turned dark brown but those from horticultural rhododendrons didn’t.
 
 
 
 
 
　Specimens：

On Rhododendron oldhamii: Taipei, Dingshan, 10 Oct 2004, NTUPPM-402; Taipei, Cai-gong-keng, 16 Feb 2005, NTUPPM-415; Taipei, Sinshan-Menghu, 9 Apr 2005, NTUPPM-430; Nantou, Piluchi, 22 May 2005, NTUPPM-568; NTUPPM-575; Taipei, Dingshan, 13 Feb 2006, NTUPPM-598; Taipei, Sinshan-Menghu, 4 Mar 2006, NTUPPM-604; Taipei, Sih-du nursery garden, 17 Mar 2006, NTUPPM-609. On horticultural Rhododendron sp.: Yangmingshan National Park, 3 Oct 2004, NTUPPM-400; Yangmingshan National Park, Er-zih-ping, 17 Oct 2004, NTUPPM-403; Yangmingshan National Park, Er-zih-ping, 19 Dec 2004, NTUPPM-409; Nantou, Chi-tou, 10 Feb 2005, NTUPPM-412; NTUPPM-413; Taipei, Danshuei, 14 Feb 2005, NTUPPM-414; Taipei, Muja, 20 Feb 2005, NTUPPM-416; NTUPPM-417; Kaohsiung, Shanping , 10 Mar 2005, NTUPPM-421; Taipei, Nangang, 27 Apr 2005, NTUPPM-501; Nantou, Huoshe, 4 May 2005, NTUPPM-548; Yangmingshan National Park, 13 Feb 2006, NTUPPM-599; Kaohsiung, Liouguei Township, Feb 2006, NTUPPM-600; Taipei, Muja, 5 Mar 2006, NTUPPM-605; Taoyuan, National Central University, 16 Mar 2006, NTUPPM-607; Taipei, Sih-du nursery garden, 17 Mar 2006, NTUPPM-610; Nantou, Chi-tou, 25 Mar 2006, NTUPPM-612.
 
 
 
　Habitat： On leaves.
 
 
 
　Distribution：

Worldwide
 
 
 
　References：

Sawada, K., 1922; Shih, H. H., 2006.
   
   
   
　Provided：

Shih, H. H. and Hsieh, H. J.
 
 
　Note： The symptoms and morphology of Exobasidium from horticultural rhododendrons were similar as E. japonicum, but they didn’t exude dark pigment. On the other hand, the taxonomy of E. formosanum first discovered by Sawada in Taiwan was identified as the synonym of E. japonicum (unpublished).