ASCOIDEACEAE 141 



of conidia that are multinucleate and, on germination, either bud 

 or give rise to coenocytic hyphae. Hyphal tips give rise apog- 

 amously to multispored asci. Uninucleate ascospores are de- 

 limited in such a manner as to leave unused a portion of the 

 cytoplasm; that is, by free-cell formation, such as occurs in Euas- 

 comycetes. The ascospores are extruded in a long, coiled, ge- 

 latinous mass. They are hat-shaped. Before germination asco- 

 spores become two- to several-nucleate and either give rise 

 directly to hyphae or else fuse and then form coenocytic hyphae. 



Fig. 46. Eremasciis albidiis. A to C. Stages In fusion of antheridial and 

 oogonial branches to produce the eight-spored ascus, in D. (Adapted 



from Eidam.) 



Whether nuclear fusions also occur at the time of hyphal fusions 

 is not established. The asci may proliferate repeatedly, as do 

 sporangia in the Saprolegniales. 



The account by Varitchak (1931) differs from that of Walker 

 in showing the fusion of a pair of "privileged" nuclei in the 

 ascus with degeneration of supernumerary nuclei. 



Spermophthora gossypii, critically and comprehensively studied 

 by Guilliermond (1928), occurs on cotton flowers in India. He 

 cultivated it on carrots and potatoes or on decoctions of these 

 vegetables. Its mycelium is coenocytic and may produce buds in 

 yeast-like manner. At the time of gametangial formation seg- 

 ments of the mycelium containing 6 to 8 nuclei become swollen, 

 and after 2 or 3 successive nuclear divisions 25 to 40 fusiform 

 gametes are developed. The gametangium then dehisces, and the 

 liberated gametes fuse In pairs. If they do not mate, thev de- 

 velop parthenogenetically. The resulting zygote may germinate 

 immediately by hyphal formation. Each hypha is septate, and 



