142 



THE ASCOMYCETES 



the cells are uninucleate, each containing a diploid nucleus. This 

 hvpha is therefore the homologue of the ascogenous hypha. The 

 asci are borne apically on the ascogenous hyphae, and usually 

 each ascus contains 8 haploid ascospores. 



Fig. 47. Spermophthora gossypii. A. Yeast-like buds may arise laterally 

 from the hyphae. B. The hyphae become segmented; each segment is 

 swollen, contains many nuclei, and is a potential sporangium. C. Sporan- 

 gium containing fusoid sporangiospores. D and E. Fusion of spores 

 through connecting tube. F. Germination of zygote with formation of 

 asci at apices of hyphae, each ascus having eight small, fusoid ascospores. 

 G. Germination of ascospores. (Adapted from Guilliermond.) 



Dipodasciis albidits is best understood from work by Juel (1902, 

 1921), whose first studies of it were published in 1905. He found 

 it in exuding sap from birch, in which it appeared as fioccose, 

 branched, septate, multinucleate mycelium. From neighboring 

 hvphal cells of the same or from different hyphae a pair of lateral 

 protrusions arises. Each protrusion contains 10 to 12 nuclei. 

 These protrusions (gametangia) soon come into contact, where- 

 upon a pore is developed, permitting the two protoplasts to 



