THE FUNGI. 



137 



FIG. 75. Grape Mildew, Uncinula ampelopsidis. b, a small piece of myce- 

 lium bearing liaustoria at d, d, and spores at e ; c, a spore germinating ; 

 a, a perithecium, i.e., a spore case that develops late in the season. (After 

 Scribner.) 



which grow as parasites on living plants or as saprophytes 

 on decaying plants. Besides the characteristic reproduc- 



FIG. 76. Apple Powdery Mildew, a, mycelium bearing hyphae, c, which in 

 turn bear chains of summer spores, 6 ; cl, perithecium or winter spore case. 

 Magnified. (After Burrill.) 



tion by ascospores, many of these plants bear ordinary 

 spores in gonidiophores that are raised on stalks. There 



