CRONARTIUM 317 
Teleutospores. Columns hypophyllous, cylindrical, curved, 
up to 2 mm. long, crowded especially along the veins of the 
leaf, sometimes covering the whole leaf, orange to brownish- 
yellow ; spores oblong, smooth, reaching 70 u long x 21 wu broad. 
Aicidia on stems and branches of Pinus Cembra, P. monti- 
cola, P. Strobus, March—June; uredo- and teleutospores on. 
Ribes nigrum, R. rubrum, etc., ‘July—October. Uncommon 
except when imported; Surrey, King’s Lynn, Exeter, West- 
bury, Woburn, Windsor Forest, Perth, etc. (Fig. 240.) 
Fig. 240. GC. ribicola. a, spore of Peridermium Strobi; b, the teleutospore- 
columns on leaf of Red Currant (reduced); ¢, uredospore; d, top of a 
column of teleutospores, x 600. 
This dangerous parasite, sometimes called the Weymouth Pine Rust, 
is confined in its ecidial stage to the five-leaved Pines ; it is reported on 
the continent also on P. excelsa and P. Lambertiana. The ecidiospore is 
distinguished from that of Peridermium Pini and P. Cornui by the fact 
that a great part of the surface is smooth. The attacked trees are 
stunted, the tops show a bushy growth that can easily be recognised ; 
the part where the mycelium is growing is swollen. In the Currant, the 
attacked leaves become thicker in texture, and different in colour. 
It was first discovered, in this country, at King’s Lyun by Dr Plow- 
right, who found the Cronartium on leaves of black, white, and red 
currant on July 3, 1892. On August 13 he exhibited in London a branch 
of P. Strobus affected by the mycelium of the alternate stage; the tree 
grew about fifteen yards away. from the currant bushes. On March 19, 
1893, he found the Peridermium in full perfection at the same place. 
Though the ecidium occurs in Europe chiefly on the Weymouth Pine 
(P. Strobus), yet that cannot be its original host, since neither Cronartium 
ribicola nor Peridermium Strobi was found in America (the home of 
P. Strobus) until the fungus was imported on it from Germany. P. Cembra, 
