CRONARTIUM RIBICOLA 55 
The life-cycle may thus be represented as follows: 
Basidiospore 
Gametophyte Mycelium 
(m generation) Acidium Spermogone 
\ Female cells Spermatia 
Fusion-cell 
| 
Spore-mother-cell 
h 
eee 4 Aicidio-teleuto-spore Intercalary cell 
ome) 
aa a 
0 00 oOo Basidiospores ° 
This life-history 1s especially worthy of consideration because 
it probably represents that which obtained at the first evolution 
of the higher Uredinales. The various types of development, 
seen in the genera Puccinia, Uromyces, etc., and described 
under the names Eupuccinia, Micropuccinia and so on, may all 
be derived from this original form. See Grove, New Phytologist, 
1918, p. 89. 
Cronartium ribicola. 
Tue Rust OF CURRANTS AND FIVE-LEAVED PINES. 
This disease, called the Currant Rust in one stage, and the 
Weymouth Pine Blister Rust in the alternate stage, can do 
enormous damage in the second phase ;"it threatens in places 
to put a stop entirely to the cultivation of the Weymouth Pine. 
It has been imported into England and the United States with 
young trees of the latter from the continent of Europe. The 
remedy is to inspect Weymouth Pines, in nurseries and plan- 
tations, annually, cutting down and burning all those that 
show infection, and to remove all currant bushes from their 
neighbourhood. A currant-free belt, 300—500 ft. wide, is 
considered sufficient for security. 
The teleutospores are produced on leaves of various kinds 
