138 



Mycologia 



in the New York Botanical Graden and several other herbaria. 

 The conidial stage was named Sphaeronema comeum C. & E. 

 (1878) and distributed as No. 2074, E. & E., N. A. F. and the 

 pycnidial stage was distributed as Leptothyrium protuberans 

 Sacc. No. 733, E. & E., N. A. F. 



CULTURES AND INOCULATIONS 



The small, curved, hyaline spores of both conidial and pyc- 

 nidial stages are produced abundantly and are easily recognized. 

 As they germinate readily on all ordinary nutrient media, it is 

 not difficult to obtain pure cultures by the poured plate method. 

 On two per cent cornmeal agar the young colonies' show a white 

 mycelium, the branches of which unite in fascicles projecting 

 above the surface of the agar. The sporodochia appear on 

 poured plates about the third day and in test tube cultures about 

 the fifth or sixth day. In both tubes and petri dishes they are 

 frequently arranged concentrically. In old cultures on potato 

 agar the sporodochia become brownish or almost black. On four 

 per cent potato dextrose agar there is much greater aerial growth 

 of mycelium and very small white sporodochia are formed in 

 the water of guttation while those below on the agar are brown, 

 especially when old. 



Cultures of the conidial stage were obtained from strawberries 

 in the market and inoculation experiments were carried out to 

 determine whether the rot could be readily produced by artificial 

 inoculations. As it is impracticable to thoroughly sterilize the 

 surface of berries, clean, fresh fruit was chosen, the berries set 

 on the calyx end in damp chambers and inoculated at the tip. A 

 drop of water containing conidia was simply placed on the end 

 of the berry or the epidermis punctured with a needle, or rubbed 

 lightly. The controls sometimes developed sporodochia, espe- 

 cially those which had been punctured. The sporodochia orig- 

 inate subcuticularly or intraepidermally. Berries that are inocu- 

 lated by puncturing will always develop sporodochia unless 

 Rhizopus appears at once and prevents. The results of a large 

 number of experiments show that only a slight injury to the epi- 

 dermis is necessary to bring about infection but we have no proof 



