270 
STRUCTURE AND LIFE HISTORIES 
(Fig. 185). The cells from this point on, to the forma- 
tion of the ascus, are diploid, and therefore constitute the 
sporophytic generation. 
FIG. 195. Lilac mildew (Microsphcera Alni). A, perithecium, with 
appendages; B, perithecium, showing asci (a); C, an ascus, containing 
ascospores; D, conidiophore (cpK), bearing a chain of conidia (conidio- 
spores, c.s); E, beginning of fertilization; anth, antheridium; car, carpo- 
gonium; F, later stage in fertilization; the contents of the antheridium and 
carpogonium have fused; /, fusion of the two nuclei; G, germination of 
ascospore (a.s); g.t, germ tube. (E and F after R. A. Harper.) 
226. Germination. When an ascospore germinates it 
develops directly into a mycelium. 
263. Life-cycle. The life-cycle of Microsphcera may 
be tabulated as follows: 
