THE SYNCHYTRIA IN THE VICINITY OF STANFORD 

 UNIVERSITY. 



By JAMES McMuRPHY, Instructor in Botany. 



THE GENUS Synchytrium belongs to the Chytridiales, the lowest 

 order of true fungi. The majority of the simple forms making 

 up this order are parasitic upon protozoa, algae and other fungi, but 

 the Synchytria and some others are parasitic upon higher plants. All forms 

 yet found here belong to the sub-genus Eusynchytrium, in which both resting 

 spores and summer sori are present. And it is the so-called summer sorus 

 that is meant in this paper when the word sorus is used, and not that formed 

 directly by the germination of the resting spore. There are no sori formed 

 here in summer. 



Most of the parasitic fungi are supposed to attack only one species of 

 host or to be limited to plants nearly related botanically, but the Synchytria 

 are not supposed to be so limited. The hosts given for S. globosum of 

 Europe are "Violaceae, Rosacese, Compositae, Rubiaceae, etc.," plants of 

 widely different botanical orders. I have seen no account of any Synchytrium 

 having been transferred from one host to another under laboratory condi- 

 tions. Since the species of Synchytrium are distinguished by the presence or 

 absence of sori, the shape and general appearance of the galls produced, and 

 the shape and size of the resting spores, it may be asked if these characters 

 would be so modified by a change of host as to make the fungus unrecog- 

 nizable. 



In April, 1910, I found near Stanford University what appeared to be 

 a Synchytrium growing on Amsinckia intermedia and took a small quantity 

 to the laboratory, where I found the material to contain both sori and resting 

 spores. Some days later I gathered more material and found that only rest- 

 ing spores were present, sori not having been formed during the ctear, warm 

 days preceding. At the same time I found growing with the Amsinckia, 

 Erodium cicutarium bearing S. papillatum with only resting spores. Now S. 

 papillatum is known only from California and is supposed to be indigenous 

 here, though it is found only on the above named host, which is a weed intro- 

 duced from Europe. 



As there were no more long periods of wet weather, I was unable to get 

 any zoospores for cross infections, but in March of the following year I had 

 an abundance of zoospores from both forms. I was unable to infect Am- 

 sinckia with zoospores from Erodium or to infect Erodium with those from 



