52 CRANBERRY DISEASES. 



at first, but when fully mature become pale greenish yellow. They 

 vary in size from 9 to 18 by 5 to 7.5 fji (PL III, fig. 8). 



Appressoria, or chktmydospores. — In badly decayed berries and in 

 old pure cultures the irregular dark-colored bodies have been found 

 which have been called chlamydospores by some authors and appres- 

 soria by others (PI. Ill, figs. 4 and 5) . The work of Fisch,='^ Frank,='« 

 Hasselbring,-'- and others seems to show that the primary function 

 of these organs is that of an appressorium. In the case of the 

 cranberry anthracnose, at least, they may also function as repro- 

 ductive bodies. Some of those found in the interior of a decayed 

 berry (PI. Ill, fig. 4) were carefully transferred to culture media 

 and were found to germinate and produce a luxuriant growth of 

 mycelium and conidia. It has been urged that they show no pro- 

 vision for distribution, as spores or reproductive bodies should. 

 When produced in the interior of berries, however, they appear to 

 show even less possibility of functioning as appressoria. The bodies 

 as found in fruit and old cultures are someAvhat variable in form 

 and appearance, but agree in general with those produced upon the 

 germ tubes arising from conidia. The light-colored spot frequently 

 observed and regarded by some as a germ pore is quite as frequently 

 wanting in the cases we have observed. Though probably primarily 

 functioning as appressoria, these bodies under certain conditions 

 appear to serve the purpose of a resting spore or chlamydospore. 



Cultures of Glomerella rufomaculans vaccinii. — Cultures made 

 from berries affected with anthracnose and from leaves have in most 

 cases produced conidia only, but in four instances the ascogenous 

 stage was also produced. The berries were from Massachusetts, New 

 Jersey, and Wisconsin. 



Cultui^s have also been made from leaves containing mycelium as 

 well as from conidia and ascospores. The growth in all cases is 

 essentially the same in appearance. The conidia germinate readily, 

 sending forth one or more germ tubes, which soon begin to branch 

 and then form a rather dense pure white mycelium. This on steril- 

 ized corn meal spreads rapidly until the surface of the medium is 

 covered with a compact layer of the fungus. On poured plates of 

 beef agar the growth of the mycelium is nuich less luxuriant. 

 Acervuli of conidia begin to appear in three or four days, and these 

 are frequently followed by the formation of dark-colored bodies 

 resembling the fundaments of perithecia. These bodies, however, 

 have never produced mature asci on agar cultures. 



The germination of the ascospores and the subsequent growth and 

 development of the mycelium are essentially the same as in the case 

 of the conidia. Cultures from ascospores on poured plates of beef 

 agar only produced conidia and what appeared to be young perithe- 



110 



