GERMINATION OF ACIDIOSPORES 7 
tapping are mature enough to germinate, and even they, owing 
to their thin walls, may lose this power in a few days according 
to circumstances. Especially can they be killed by rapid 
| 
Fig. 5. P. Caricis. a, three cells of the peridium, on Nettle ; b, a cell in 
optical section; c, the same in surface-view ; d, two xcidiospores. x 600. 
drying. Instances are known, however, where some of them, 
kept in a cool place, retained their capacity for germination 
about seventy days, though most of them were dead after 
eighty days. 
Each spore has a number of germ-pores; in Puccinia Caricis 
the number is about five or six; in other species of Uredinales 
the number varies from two to eight. 
These pores, which are scarcely visible 
until germination begins, are thin places 
in the inner layers of the outer wall, the 
whole cell bearing a close resemblance to 
many kinds of pollen-grains (microspores). 
(Fig. 6.) 
It is worthy of notice that in the 
spores of Endophyllum, and others of the 
less-advanced type,there are no real germ- 
pores; the germ-tube merely forces its/ ; mo, 
way out at the first place that gives way. gy ped Soak 
From this state of things there isa gradual _in water. x 180. 
transition from numerous to few germ-pores, in the highest 
types of all (Uromyces and Puccinia teleutospores), each cell 
has one and only one well-defined germ-pore. 
