STUDIES OF GLOMERELLA FROM DIFFERENT HOSTS. 39 



other hosts, there appear to be fertile and sterile strains so far as the pro- 

 duction of ascospores is concerned. Fertile perithecia have been pro- 

 duced in flasks of corn meal by transplanting portions of an apple taken 

 from just beneath the skin where ascogenous perithecia were formed, 

 and subcultures from these have continued to produce perithecia. 



Leaves from trees badly affected with bitter-rot produced acervuli 

 of Glomerella in abundance when kept in a sterile moist chamber. 

 From this host, as from others, a strain of the fungus is sometimes 

 obtained which produces peritheciumlike bodies in which no asco- 

 spores develop. 



CULTURES. 



Fifteen tube cultures, made September 14, using conidia from 

 acervuli on different bitter-rot spots on a Willow Twig apple from 

 Vienna, Va., all developed perithecia but no acervuli. In five of the 

 tubes the perithecia were fertile, producing asci and ascospores. 

 The other 10 produced only immature or sterile perithecia. Apples 

 inoculated with ascospores from these cultures developed bitter-rot, 

 followed by the production of fertile perithecia but no acervuli, 

 indicating in this strain the great predominance of the perithecial 

 form. Cultures made from apple leaves from West Virginia, obtained 

 from Mr. Rand, produced perithecia with asci somewhat smaller than 

 usual, as shown in Plate III, figure 39. Cultures of this form grown 

 on sterile apple twigs also showed a few brownish ascospores. 



The spore measurements of Glomerella as found on this host and 

 in cultures are as follows : Asci from fruit in moist chamber 69 to 78 

 by 6 to 10.5 fi, in cultures 54 to 110 by 7.5 to 13 ji; ascospores from 

 apple 15 to 21 by 4.5 to 6 /*; ascospores in cultures 13.5 to 21 by 

 4.5 to 6 pt. Variations in the asci from this host are shown in Plate 

 III, figures 35 to 39. Plate I, figures 3 and 3a, also shows an ascus 

 and ascospores of the same. 



CHROMOGENIC FORM. 



On November 16 four plates of corn-meal agar were poured from a 

 single acervulus of Glomerella from an apple from Vienna, Va., which 

 had been kept in moist chamber in the laboratory. These cultures 

 produced an abundance of acervuli and chlamydospores. In the 

 dilute plates the acervuli were numerous; in the thickly sown plates 

 acervuli were almost entirely wanting and the conidia scattered. 

 These cultures when about a week old began to take on a pinkish 

 color, the color apparently being developed in the agar and not in the 

 mycelium of the fungus. Four tubes inoculated by transfer of spores 

 from four different acervuli from this same plate were made to deter- 

 mine whether this chromogenic character was possessed by other 

 acervuli and whether it persisted. Four days later a slight pinkish 



252 



