236 



Journal of Agricultural Research 



Vol. XIX, No. s 



The spores, both conidia and ascospores, behaved alike in germination. 

 They germinated, as described by Wollenweber, by imbibing water, 

 increasing the number of septa (fig. i , A, C) , and forming several myce- 

 lial strands from the different cells (fig. i, C). When the cultures were 

 grown in a saturated atmosphere, conidia were cut off from lateral 

 branches of mycelial strands in 24 hours (fig. i, B, D). In 48 hours a 

 copious conidial production took place in definite sporodochia-like 

 clusters (fig. i, E). On extremely moist plates these clumps occasion- 

 ally massed together to form a pionnotes. As mycelial development 



Fig. I. — Conidial production in Gibberella saubinetii (Mont.) Sacc: A, Ascospwres froiu cornstalk, germi- 

 nated in distilled water, producing conidia in three days; B, D, typical conidia and conidiophore from 

 a 2a-hour-old hanging drop culture from a conidium from A; C, germinating conidia from a s2-hour-old 

 plate culture; E, conidiophore and germinating conidia from a 47-hour-old colony in a Van Tiegham 

 cell. This colony was three generations from an ascospore. Potato^iextrose agar acidified with lactic 

 acid was used unless otherwise stated. 



progressed, new conidial masses developed and thus gradually in- 

 creased the size of the pionnotes. 



The conidia were pushed off the conidiophore before septation was 

 completed, and new conidia formed in their place (fig. i, E). Septation 

 was completed after the conidia had been separated from the conidio- 

 phore. The conidia became swollen, septation increased, and germi- 

 nation took place in from 6 to 12 hours after leaving the conidiophore 

 (fig. I, B, C, E). When the cultures were moderately crowded and 

 moisture and temperature conditions were suitable, all these conidia 

 germinated, forming a stroma; and conidia development ceased until 

 the final development of sporodochial conidia several weeks later. If, 

 however, the conidia were transferred to a suitable medium and were not 



