iqiq] KEMPTON—PYCNIDIUM 245 



The primordia of the acervuH begin their formation deeply 

 imbedded in the media, even near the bottom, by the time the cul- 

 ture is 4 cm. in diameter and no more than 4 or 5 days old. At 

 this age no conidia have developed upon the short conidiophores 

 or as buds from cells of hyphae, as often occurs when the culture 

 becomes older. The primordia arise by 2 methods: (i) from a few- 

 cells of a main hypha arise a few or many short budlike hyphae 

 (figs. 89-92); these elongate, intertwine, and branch to form a 

 cushion-like base from which very short conidiophores arise; 

 (2) hyphal branches from a few neighboring or contiguous mycelial 

 strands intertwine, some of the threads forming short loops which 

 mass, intertwine, and branch (figs. 93-96), forming an irregularly 

 shaped, loosely made, cushion-like base from which conidiophores 

 arise as in the other type. Irregular large acervuli, or acervuli-like 

 groups, bearing numerous conidia, arise in this latter type. 

 The first mentioned type may be considered as meristogenous, 

 both simple and compound modes appearing; the second is 

 symphogenous. 



The genera Gloeosporium and Colleiotrichum have been exten- 

 sively studied by Shear (36), Stoneman (42), , Southworth 

 (38, 39), Edgerton (11), and others. Late stages of development 

 and cross-sections of different stages have been figured from fixed 

 material in host tissues, but little has been said in regard to the 

 early development of the acervulus. The 3 species studied give 

 insight only into the origin of the cushion-like base from which the 

 acervulus arises. They present 2 distinct types, the simple loosely 

 woven base that arises from a single hypha or from a few contiguous 

 hyphae, and the more complexly interwoven base which arises 



symphogenously. 



Pestalozzia De Notaris 



Pestalozzia palmarum Cke.; pure culture procured from the 

 Centralstelle fiir Pilzkulturen, Amsterdam, Holland. 



A few hyphae, usually 2-6, lying side by side form a bed in 

 which a few cells begin to divide into shorter cells. These cells 

 may be in only one of the hyphae (fig. 97a), or they may be con- 

 tiguous cells of 2 or more hyphae (fig. 100). These cells swell and 

 continue to divide by cross and longitudinal walls, at length forming 



