130 



MEDICAL MYCOLOGY 



in the lack of ascogenous hyphae, it has nothing in common with that group, 

 and is intermediate between the Spermophthoraceae and the Ashbyaceae. 



In Eremofheciuni (Fig. 16), the mycelium is multinucleate and rarely sep- 

 tate. The genus has not been carefully investigated cytologically, but the 

 gametangium (or ascus?) resembles that of Spermophthora in shape. The spore 

 number is somewhat less. The spores are fusiform, rounded at one end, taper- 

 ing to a long filiform appendage at the other. They are arranged in the ascus 

 with the rounded ends in contact and the filiform appendages gathered in a 

 fasicle at the poles, giving the whole spore mass the appearance of a huge 

 nuclear spindle. This grouping suggests that figured by Horta (1911) for 

 Piedraia. The protoplasm of the spore is much denser in the end opposite the 

 appendage, and germination takes place only in the end of the spore with the 

 dense protoplasm. No septum has been detected separating the spore into two cells. 



Yig 16. — Ashbya Gossypii. 1, mature spore; Z, S, germinating spores; i, mycelium; 5, 6, de- 

 velopment of gametangium; 7, mature ascus with ascospores. (After Guilliermond 1928.) 



In Ashhya Gossypii, a parasite on cotton, the mycelium is septate but the 

 cells are multinucleate. Sexuality has been lost, the asci developing partheno- 

 genetically. The nuclei divide twice, forming the tetrads which precede 

 spore formation. This is reminiscent of sporangiospore formation in Piloholus 

 and will be encountered several times in other lines of this group. The 

 number, both of nuclei and of nuclear divisions, is reduced and stabilized so 

 that ordinarily either 8 or 16 spores are produced. The spores are usually 

 rounded at one end and taper at the other into a long slender projection, sug- 

 gestive of a flagellum, but without motility. 



In Nematospora, which is also parasitic on plants, degeneration has pro- 

 ceeded further until sprout cells as well as mycelium are produced ; the spores 

 are long fusifonn to acicular and reduced to 8 per ascus (very rarely 16, or 



