HOTSON. — CULTURE STUDIES OF FUNGI. 253 



up which eventually enclose this group of large cells. These branches 

 which divide up into short cells, form the wall of the perithecium. 



Sometimes, as in the case of the bulbil, a terminal cell may become 

 the primordium, as is evidently the case in Figure 10, Plate 2, where 

 there are two large cells which have originated from a terminal one. 



The mature perithecium is straw-colored, globose or slightly piri- 

 form, measuring 400-500 /i in diameter, but often much smaller than 

 this, the variations in size are largely due to the character of the 

 medium on which it grows. It is surmounted by a crown of setae 

 which surround the ostiole and are colorless, 100-170 jx in length, 

 stiff, erect, straight, and tapering to a point. There are no lateral 

 setae of this nature, but frequently superficial cells near the base of 

 the perithecium may send out filaments which serve as attachments 

 to the substratum. The perithecia often occur grouped in consider- 

 able numbers and not infrequently two or three are found which have 

 more or less fused during their development, having no doubt arisen 

 from primordia which were in close contact with each other. Some 

 time after their formation the cirri of ascospores begin to assume a 

 whitish appearance which is due to the presence of numerous germi- 

 nating spores producing many abnormalities. A very common form 

 in such cases is shown in Figure 14, Plate 2 where, instead of a regular 

 germ tube, a large opalescent, spherical body is formed at the end of 

 tin spore, which contains a great deal of granular material and stains 

 deeply. Occasionally a second such body is produced, and from 

 these one or more lateral branches may arise (Figures 18-20, Plate 2). 

 Not infrequently a series of these swollen cells appears terminating a 

 branch and these become spherical and form a bulbil-like structure 

 (Figure 17) such as is sometimes met with in Van Tieghem cell cultures 

 (Figure 21). One of the most striking features of these germinations 

 is the copious formation on the germ tubes of ovoid conidia which 

 arise from bottle-shaped sterigmata and usually adhere in short 

 chains, although they sometimes cohere at the tips of the sterigmata 

 in a spherical mass. As already mentioned conidia similar to these 

 are also quite frequently met with on the mycelium in all parts of 

 the culture, and when the spores collect in masses the fructification 

 might readily be mistaken for that of Hyalopus. 



In some cases the outer cells of the bulbils increase in numbers 

 until the whole structure is about half the size of a perithecium, 

 although very irregular and sclerotium-like. In each case, however, 

 the cells of the original bulbil retain their deep tan-color, while those 

 which have resulted from ibis secondary growth are distinguished 



