PHYCOMYCETES 



139 



of a cell (Fig. 42), which becomes a spore, or properly a spo- 

 rangium, producing upon germination a mass of swarm spores. 

 These spores, being dependent upon 

 abundant moisture for their distribu- 

 tion, may be rendered more or less 

 ineffective by withholding water from 

 the cranberry plants during the winter. 

 This fungus also occurs upon other 

 ericaceous plants more or less closely FIG. 42. BLACKBERRY GALL: 

 related to the cultivated cranberry. RESTING SPORE STAGE 



IV. PYCNOCHYTRIUM GLOBOSUM (Schroet.) Schroet. 



This is a parasite common in Europe and America on many 

 families of flowering plants. In the United States it has been 

 found on plants growing in the peat bogs of the eastern states, 

 some of the hosts observed being a species of violet, wild straw- 

 berry, blackberry, and maple seedlings. It causes the development 

 of small but noticeable yellow or reddish galls. 



The entrance of the swarm spore into an epidermal cell is, as 

 indicated above, followed by general growth of the protoplasmic 

 mass. The affected epidermal cell may become somewhat in- 

 vaginated, but the enlargement due to the growth of the fungous 

 cell within is such as to give the appearance of a minute gall. 

 The resting spore is shown in Fig. 42 as it appears in mid- 

 summer. Later there results, as indicated, the sporangial sorus, 

 each sporangium of which, upon germination, produces the char- 

 acteristic uniciliated swarm spores. 



V. CHYTRIDIALES: OTHER SPECIES 



Among other Synchytriaceae more or less commonly found in 

 the United States are Synchytrinm decipiens Farl. on the hog 

 peanut, Amphicarpa monoica ; Synehytrium fulgens Schroet. on 

 the evening primrose, (Enothera biennis ; Pycnochytrimn aurcnm 

 (Schroet.) Schroet. occurring upon numerous hosts ; and Pycno- 

 chytrimn Myosotidis (Kiihn) Schroet. on certain Boraginaceae and 

 Rosaceae. In a different family, Oochytriaceae, may be included 

 some interesting parasites of economic plants. These fungi 



