112 DUDLEY MEMORIAL VOLUME 



Amsinckia. In March of this year, I placed an inch or so of the ends of the 

 leaves of a few potted Erodiums and Amsinckias into a vessel of water con- 

 taining zoospores of the Synchytrium on Amsinckia. After about two hours 

 the plants were removed to a damp place. Some of the leaves of Amsinckia 

 developed an abundance of Synchytrium on the ends that had been immersed 

 in the water, but there was none on the Erodium. I have had no zoospores 

 for further experiment. 



In the hills I have found Erodium cicutarium growing with Erodium 

 botrys, nearly every plant of the former more or less discolored by Synchyt- 

 rium papillatum, but the latter entirely free of the parasite. Near the 

 Museum and the Nursery, I found Erodium cicutarium growing with Ero- 

 dium moschatum, the one often discolored with Synchytrium, the other with 

 none. These two species of Erodium are so similar in appearance that be- 

 ginners in botany often find it difficult to distinguish them, but the Synchyt- 

 rium zoospores seem to have no such difficulty. 



If Synchytrium papillatum is really endemic on some native California 

 plant, then, since we have no native Erodiums, it must have passed to E. 

 cicutarium from some host much farther removed botanically than either of 

 the two mentioned above. 



The following species of Synchytrium have been found in the vicinity 

 of Stanford University: 



SYNCHYTRIUM PAPILLATUM Farlow. 



Synchytrium papillatum Farlow. Bull. Bussey Inst. 2 :239. Bot. Gaz. 

 10:239, 1885. 



"Spots dark purple, galls glandular, formed of papillate, pyriformly 

 swollen epidermal cells, resting spores elliptical, .06-.07 mm. by .04-.05 mm., 

 epispore brown, somewhat roughened. Sori superficial, spherical, .10-. 12 mm. 

 in diameter." 



"On leaves of Erodium cicutarium L'Her. California." 



In late winter and early spring this species may be found on the slopes 

 of the hills as well as in the valley, and often there are places where it is 

 difficult to find plants of the Red-stemmed Filaree that are entirely free of the 

 deep red (dark purple when dried) discolorations caused by the parasite. 



The galls vary considerably in size and may be nearly regular in outline 

 or irregular and strongly papillate. Usually there are only one or two rest- 

 ing spores in a gall, but there are sometimes four or five. The sori are 

 spherical, flattened or elongated and contain about 45-70 zoosporangia 

 15-21 x 15-26/i in diameter. In material taken after a week or two of rainy 

 weather I have found sori more abundant, but after a few days of sunshine 

 only resting spores. 



