368 



terial from Spartina Michanxiana and on Spergula canadensis from 

 Spartina glabra var. alternifoHa and on Spergula canadensis from 

 Spartina patens. 



In 1912 Arthur again conducted cultures (Mycol. 7:77. 1915) and 

 obtained infection and development of aecia on Collomia linearis when 

 telial material from Colorado was used. 



From these successful results, taken together with the negative 

 results recorded by the investigators mentioned, it would appear that 

 well marked biological races of this species exist or that distinct species 

 are here included. 



Orton (Mycol. 4:202. 1912) pointed out that it is not possible to 

 distinguish this species from Pnccinia Distichlidis E. & E., the telial 

 stage of which occurs on Spartina sp., except in the possession of one- 

 celled teliospores. Arthur in 1915 (Mycol. 8:136. 1916) has shown 

 that the aecial stage of the Puccinia develops on Steironema and is 

 morphologically identical with Aecidinm Polemonii, thus strengthening 

 the morphological evidence of the relationship between the two forms. 



117. Uromyces Polygoni (Pers.) Fuckl. Symb. Myc. 64. 1869. 

 ruccinia Polygoni Pers. Neues Mag. Bot. 1:119. 1794. 



Nigredo Polygoni Arth. Result Sci. Congr. Bot. Vienna 344. 1906. 

 On Polygonaceae : 



Polygonum ariculare L., Newark, Aug. 17, 1907, III, (1712). 

 Polygomim erectiim L., Newark, September 1888, F. D. Chester, 

 June 21, 1907, II, (1668). 



118. Uromyces Pontederiae W. Gerard, Bull. Torrey Club 6:.'^1. 1875. 

 Nigredo Pontederiae Arth. N. Am. Flora 7':238. 1912. 



On Pontederiaceae : 



Pontederia cordata L., Milford, Sept. 1, 1892, A. Commons 

 (1986). 

 This species is evidently rather rare, having been recorded in North 

 America by Arthur (1. c.) in but four states on the Atlantic coast from 

 New York to Florida and in Missouri. Only four other collections are 

 known to the writer. It also occurs in South America. This species is 

 assumed to be autoecious though no aecia have been found. 



