284 



Mycologia 



222. Nov., 191 3). I to concludes, therefore, that the leaf -inhabit- 

 ing Gymnosporangium^ (G. haraeanum = G. asiaticum) is the 

 cause of the Japanese pear-rust (Roestelia koreaensis) , while the 

 stem-inhabiting form (G. japonicum) is connected with the Pho- 

 tinia rust (Roestelia photiniae P. Henn.). (See 1. c. p. 221, and 

 also in Byochu-gai Zasshi, Journ. PI. Prot. 4 3 : 178-182. T. 6, iii, 

 Mar., 1917. Japanese.) Jackson also succeeded in infecting 

 sand-pear and quince with the teliospores from Gymno sporangium 

 koreaensis Jacks. (= G. asiaticum=G. haraeanum) and recom- 

 mended G. photiniae Kern (in Bull. N. Y. Bot. Gard. 7 : 443. 

 Oct., 191 1 ) to supersede G. japonicum, following Ito's successful 

 inoculation. (See Journ. Agr. Res. 5: 1006, 1007. Feb., 1916.) 

 Dietel, on the other hand, made examination of aecia found on the 

 leaves of Cydonia vulgaris, Pirus sinensis and Pourthiaea villosa 

 (Photinia villosa) collected by Kusano at the Botanic Garden, 

 Tokyo, and brought altogether under one species G. confusum 

 Plowr. (in Engler's Bot. Jahrb. 28 s : 286, May, 1900), but Ito 

 states that G. confusum never occurs in Japan, though Shirai lists 

 it in his Nippon Kinrui Mokuroku (A list of Japanese fungi hith- 

 erto known, Tokyo, Nippon Engei Kenkyukwai, M. 38, 1905, p. 

 39) and he also maintains that the first two must be identical with 

 G. asiaticum and the third must be G. japonicum (in Byochu-gai 

 Zasshi 4 3 : 180. Mar., 1917). 



In Korea, pear-rust was known quite early and its connection 

 with juniper was suspected by the Korean agriculturist Soh You- 

 Koh in his work Haing po chi written as early as about 1845. 

 (Shirai, in Ann. Phytopath. Soc, Japan i 1 : 2. Jan., 1918.) In 

 Japan, Hori first noticed the connection of the pear-rust with 

 juniper Gymno sporangium in 1892, and he studied the actual dam- 

 age of the pear plantation in Okayama first in 1900. (See Hori's 

 Shokubutsu Byogai Kowa [Lectures on plant diseases] v. 2. 

 Tokyo, Seibido, t. 5, xi, Nov., 1916, p. 301-302 [Japanese] .) The 

 infection of quince (Cydonia vulgaris) by the pear-rust fungus was 

 reported by Miyabe and all later investigators, but Sydow made it 

 a new species giving the name Gymnosporangium spiniferum to 

 the aecial stage. (See Ann. Mycol. 10: 78. Feb., 1912.) Ito 

 conceives this to be identical with G. asiaticum (1. c. p. 181), but 



