2I 4 



CLOSED TYPE OF ASCOCARPS 



contact of these organs permits the male gamete to pass over 

 and fuse with the female (Fig. 147, B). The growth of the 

 gametospore forms a limited number of cells, one or more of 

 which develop into asci (Fig. 147, C, D). As in Penicillium, 

 this growth becomes enveloped by a mass of hyphae that originate 

 from the mycelium. These ascocarps appear at maturity as 

 black specks and in the majority of forms they are provided with 

 hair-like outgrowths that are very regular and characteristic 

 of the genera (Fig. 148). The ends of these hairs are rather 



FIG. 148. Forms of ascocarps found among the powdery mildews : A, 

 Phyllactinia with needle-like appendages enlarged at the base. B, Micro- 

 sphaera, appendages dichotomous at apex. C, Uncinula, appendages coiled 

 at apex. D, Erysiphe without appendages and crushed to show escaping 

 asci. E, an ascus containing six ascospores. 



mucilaginous and may assist in the dissemination of the asco- 

 carps. The ascospores are resting spores adapted to enduring 

 drought and cold as in Penicillium, which they resemble in their 

 discharge and germination. 



87. Forms with Slightly Opened Ascocarps. Several orders 

 of the Ascomycetes are distinguished from the preceding group 

 by the formation of ascocarps that are slightly open. (Figs. 151 ; 

 152, B). In this way, provision is made for the discharge of 

 the ascospores without the decay of the ascocarp. Only two of 

 these orders can be noticed. 



