318 DISEASES OF CULTIVATED PLANTS 



ance and structure, but differs biologically. The secondary 

 spores produced by the teleutospores will not infect pear- 

 tree leaves, but will infect and give origin to aecidia on 

 leaves of medlar, quince, and hawthorn. 



Aecidia on thickened reddish spots on the leaves, cylindric- 

 fusiform, opening by lateral rifts, at length fimbriate, aecidio- 

 spores subglobose, pale brown, 15-20 /x diam. Teleutospore 

 masses at first tubercular, dark chocolate-brown, almost 

 black, soon cylindrical, often compressed, becoming rich 

 chestnut-brown ; teleutospores smooth, oval or elliptical, ends 

 acute, of two kinds, some orange-yellow, others dark brown 

 with thick walls, 40-50 x 20-25 l M '> pedicel long. 



Plowright, Brit. Ured. and Ustilag., p. 232. 



Mountain ash cluster-cups. Teleutospore stage on Juni- 

 peru's communis and J. nanus. It is known by the subglobose 

 shape of the soft, gelatinous spore-masses formed in spring, 

 which are dark brown then orange. The aecidium on leaves 

 of mountain ash are cylindrical, curved, soon becoming torn 

 into shreds at the tip. They occur in small clusters on 

 orange-red spots. The name of the fungus is Gytnnosporan~ 

 gium junipcrinum ( Winter). 



Spermogonia in small groups on orange spots on upper 

 surface of leaf. Aecidiospores in chains, angularly-globose, 

 brownish-yellow, delicately waited, with six germ-pores, 20- 

 2.X x 10-24 /* Teleutospores ellipsoid or oblong, i-septate, 

 40-75 X 17-27 l l , slightly tinged brown. 



Gymnosporangium Miyabei (Yamada and Miyake), a species 

 from Japan, has its teleutospore condition on Chamaecyparis 

 pisifera (S. and Z.), and its aecidium form on Pirus Miyabei 

 (Sarg.), and P. aria (Ehr.), var. kamaonensis (Wall.). 



Aecidia yellowish-brown, 3 mm. long, aecidiospores irre- 

 gularly globose or elliptical, 1S-21 ji diam., or 24/* long, on 

 under surface of leaf ; spermogonia on corresponding points 

 on upper surface. 



Teleutospore masses bursting through bark of twigs, as a 

 crust or warted mass ; mostly 2-celled, seldom 3-celled, 36- 

 80X8-20 /*. Promycelium spores 12-18x7-11 /' 



Yamada and Miyake, Bot. Mag. (Japan), 22, p. 21, 1908. 



