NEUROSPORA 



115 



Neurospora. Under the name of Monilia sitophila, this genus has 

 been known for a long time in its imperfect stage. Several years 

 ago it was found that ascospores were formed readily and more 

 recent studies on cytology and genetics by Shear, Dodge, and Lind- 

 gren (see Chapter II) have made this one of the most completely 

 known of fungi. Because the commonest species of the genus, Neuro- 



FiG. 67. 1, 2, and 3, H elminthosporium sativum; 5 and 6, Curvularia geniculata. 

 X800. Prepared from outline camera lucida drawings of Dr. Roderick Sprague. 



spora sitophila, is heterothallic, the ascospores are large and easily 

 isolated mechanically, and growth and sporulation are easily in- 

 duced, this species and mutants of it are excellent "tools" for 

 geneticists. (See Fig. 68.) 



Since N. sitophila is heterothallic, only the conidial stage will 

 ordinarily be encountered in routine bacteriological work. Conidia 

 are borne from short hyphal branches and the chains are much 

 branched. See Fig. 69. They develop in the same manner as those 

 of Cladosporium. The conidia are cylindrical to ovate and are nu- 

 merous and bright orange-red in color. This together with the fact 

 that the mycelial growth is so copious and floccose, often ascending 

 for several centimeters in the culture tubes, gives the mold a char- 

 acteristic appearance in culture. 



