92 



PLANTS AND MAN 



we find the bread molds, the mildews, and a few plant parasites 

 (figs. 23, 61). Reproduction is both sexual and asexual, in the 

 latter case involving simple spores in rather unspecialized 



Fig. 61. — The algae-like fungi include molds (see fig. 23) and mildews, here 

 shown growing in leaf tissues. 



sporangia. Another group, the Ascus Fungi, has a more specialized 

 vegetative body and reproduces asexually by special sac-like 

 structures known as asci in which are a small and definite number 



Fig. 62. — Useful ascus-fungi include morel (A), yeast (B), and truffles (C). 



of spores. Some of the Ascus Fungi are harmless saprophytes; a 

 few are useful such as Yeast, Truffles and Morels; but many are 

 harmful plant parasites and cause a great number of plant 

 diseases (fig. 62). Plant diseases are treated at greater length 



