PLATE 24 » 



A. — Slender, sparingly branched conidiophore bearing comparatively few conidia. 

 It is only partially matured, as can be seen from the small size and rotund shape of the 

 conidia and from the incomplete development of the septum. From maize during 

 heavy dew. X 375- 



B. — Tip of branch with two conidia in situ. Treated with osmic acid and stained, 

 thus differentiating the two sterigmata as more hyaline than the branch tip. X 750. 



C. — Stout, much-branched, mature conidiophore bearing 38 spores. From maize 

 during heavy dew. X 375- 



D. — Upper portion of a nearly mature conidiophore with one secondary branch 

 which has failed to branch further and has terminated in a single conidium only. 



X375- 

 E. — Small, stunted, sparingly branched conidiophore produced on maize during 



the light dew of the hot, dry season. Note the poorly formed cell and the small size 



and restricted development of the conidiophore as a whole in comparison with those 



formed in heavy dew, as shown in A and C. X 375- 



F. — Basal cell with two thick crosswalls; From maize. X 375- 



G. — An unusual basal cell with two septa and an abnormally large footlike base. 



X375- 



H, J, L. — Typical basal cells of conidiophores. X 375- 



I. — Upper portion of an imderdeveloped conidiophore bearing three spores on 

 sterigmata arising directly from the top of the main axis. X 375- 



K. — Tip of an ultimate branch with two sterigmata bearing conidia. The right 

 conidium is shown as if in optical section, the left in surface view. X 850. 



M. — Basal cell of a conidiophore from teosinte with septum formation progressing 

 by the centripetal extension of a cellulose-pectose ring. The footlike projection at 

 the base is abnormally large. X 375. 



' The drawings were made with the aid of a camera lucida and are from fresh material, with the 

 exception of B, G, K, and M. G, I, and M are from material on teosinte; all other figur^^ are from material 

 on maize' 



