37 



The ideal ascomycetes for classroom work are the species of 

 the orange-colored monilioid molds in which the conidia or 

 asexual spores are borne in chains (Fig. 1) and which have as 

 their perfect or sexual stage the pyrenomycete Neurospora 

 (Fig. 2). The ascocarp or perithecium has a well differentiated 

 wall and ostiole, apical opening, and is small enough to be 



Figure 2. Ascocarp or perithecium of Neurospora sitophila, X200. 



examined under the microscope. The asci are few in number 

 and develop large colored spores with ribbed markings. (Plate 

 2). These fungi reproduce themselves asexually by means of 

 spores formed on dichotomously branched conidiophores. Neu- 

 rospora sitophila is the common orange-colored mold of the bak- 

 ery. N. crassa grows everywhere in the tropics on sugar cane ba- 

 gasse and on burned over places in forests. Both are heterothallic 

 or haplodioecious. A'^. tetrasperma is known only from a few 

 places as yet, but would serve the best for classroom work, be- 

 cause it is either homothallic or heterothallic, depending upon 



