1919] KEMPTON—PYCNIDIUM 241 



imbedded in the agar, although a few develop on or near the sur- 

 face. Those developing imbedded in the agar are smooth, while 

 those on the surface have a fuzzy appearance. A very feyv pycnidia 

 form by the compound meristogenous method described for Phoma. 

 These usually form 2 or more contiguous hyphae in which a few 

 adjacent cells divide, swell, continue to divide, and enlarge until 

 a primordium similar to the one described is formed. 



Sphaeropsis citricola McAlpine; isolated at Urbana, Illinois, 

 January 19 16, from a kumquat fruit {Fortunella margarita Swingle) 

 from Lake City, Florida. The condition produced on the rind of 

 the fruit was that of a very black carbonaceous spotting which 

 finally spread over the whole fruit. 



In culture a coarse brown mycelium 5-8 ju in diameter is pro- 

 duced. Numerous pycnidia 80-175 /z i^ diameter develop from 

 primordia each of which arises either from a single cell or a few 

 adjacent cells in a single hypha. This cell or group of cells (figs. 56, 

 57) divides by cross and diagonal walls (figs. 58-61), later by the 

 addition of longitudinal walls to form a rounded or elongated mass 

 (figs. 62, 63) which is slightly darker in color than the mycelium. 

 This mass becomes globose, light brown, carbonaceous and reticu- 

 lated, and is the primordium. Development is usually simple 

 meristogenous. The compound meristogenous mode is seldom 

 found (figs. 64-66) . From pycnidia developing from these masses 

 small hyaline spores 5-7X4-5 m exude. 



The genus Sphaeropsis presents a variation of the symphogenous 

 development in that the branches interweave near their ends at a 

 point some distance from the main myceHal strands (fig. 53). 

 It also shows the more usual symphogenous type (figs. 54, 55) 

 described for Macrophoma (figs. 48, 49). Simple meristogenous 

 development occurs in one species. The compound mode seldom 

 occurs in the species studied. 



CoNiOTHYRiUM Corda 



Coniothyrium pyriana (Sacc.) Shel. ; pure culture isolated from 

 twigs of apple (Pyrus mains L.) from Savoy, Illinois, October 1916. 



A few adjoining cells of a main hypha become slightly swollen 

 and divide into short cells (figs. 67, 68). These cells swell, divide 



