OOPHYTA. 141 
odgones) become greatly thickened and finally assume a 
globular shape (Fig. 69, 0); the other branches (the young 
antherids) become elongated and club-shaped (Fig. 69, 7). 
a) 
Fic. 68.—Germination of the conidia of Potato-mildew. a, b, c, formation of 
zodspores; d, growth of zodspores; sp, a z0dspore growing into the cells of the 
plant, e, i. Magnified about 400 times. 
The antherids bend and come in contact with the odgones, 
and soon each thrusts out a small tube which penetrates 
the odgone, reaching the germ-cell. The protoplasm of the 
Fia. 69.—Sexual organs of a Mildew. 0, odgones; n, antherids. A, youngest 
stage; Band C, older stages. Magnified 350 times. 
antherid is thus transferred directly to the germ-cell (Fig. 
69, A,B,C). After fertilization the germ-cell secretes a 
thick double wall, and so becomes a resting spore. - 
294. The resting spores remain in the tissues of the host 
until the latter decay, which is generally in the spring. 
