262 BULLETIN 94. 



begin to develop. Some of them and probably the first ones are 

 prostrate and wholly or partly immersed in the agar. They may 

 be simple, or branched, when the branches may be opposite, or 

 irregular, and in some cases the branches are assurgent, when 

 most of them are thrown to one side. There is a strong tendency 

 for the threads of the mycelium to assume a moniliform appear- 

 ance by the swelling of the short cells thus producing a strong 

 constriction at the septa. This tendency to a swelling of the cells 

 of the mycelium is also shown to some extent in the basidia. 

 Quite early many of the fruiting threads become erect and branch 

 several times, the ultimate branches forming the basidia. The 

 branches and the basidia are frequently opposite or whorled and 

 when standing alone simulate very well the conidial fructification 

 of a Vertidllium. For some time the conidia are held in chains 

 as they are developed successively on the same basidium. When 

 moisture is sufficient, and this is usually the case in the Petrie 

 dish, the capillarity of the film surrounding the conidia pulls 

 them from the concatenate position and they are gathered into a 

 globular head appearing as if they were developed in the form of 

 a Mucor. Very soon at the center of the colony by the develop- 

 ment of numerous fertile hyphae very closely, a true stroma is 

 formed, and the conidia are held by capillarity in great masses 

 upon the summit of the stroma. 



April 24th a cell culture was prepared in a drop of nutrient agar 

 at 5 P. -M. On the following day the conidia were germinating and 

 a group of them was photographed (46, Plate V. upper left corner). 

 The spores here at this time were 4-5 // in diameter. The germ 

 tubes are quite sinuous and at this age (17 hours from time of sow- 

 ing) were 15 /' to 25 P. long, and about 2 P. in diameter. In the ger- 

 minating spores are a few, 3 to 5, small and very strongly refringent 

 granules in the hyaline and homogenous protoplasm, and are quite 

 well shown in the photomicrograph. On the following day when 

 the culture was 40 hours old another photograph was taken (fig. 

 47). By this time many of the conidia showed the development of 

 three tubes, and the tubes were now quite long. In some cases the 

 hyphae coming in contact, anastomose, one of these conditions 

 being shown in the photomicrograph. One day later several of 

 the conidia showed still other tubes so that in time two to several 

 tubes may arise from a single conidium. The anastomosing in 



