372 



This species is distinguished from the only other Uromyces on 

 Juncus occurring in the eastern United States {U. Junci-effusi Syd.) 

 which occurs commonly on J. eff^isus, by the number and position of the 

 pores in uredospores. In U. Silphii there are two superequatorial pores; 

 while in U. Junci-effusi the pores are 3-4 and equatorial. 



124. Uromyces Spermacoces (Schw.) Curt. Cat. PI. N. Car. 123. 1867. 

 Puccinia Spei-macoces Schw. Schr. Nat. Ges. Leipzig 1:74. 1822. 

 Nigredo Spermacoces Arth. N. Am. Flora 7:266. 1912. 



On Rubiaceae: 



Diodia teres Walt., Newark, Sept. 18, 1905, (1627) ; Selbyville, 



Oct. 4, 1907, (1934) ; Cooch's Bridge, Sept. 18, 1915, C. O. 



Houghton. 



This is doubtless an autoecious form though no cultures have been 



conducted. It is a very common species in the south and south central 



States. The above collections are near the northeastern limits of its 



range. 



Unconnected Forms. 



125. Aecidium Apocyni Schw. Schr. Nat. Ges. Leipzig 1:68. 1822. 

 On Apocynaceae: 



Apocynum pubescens L., Seaford, July 9, 1907, (1649, 1653), 

 June 4, 1907, (2053); Clayton, July 24, 1907, (2253). 

 This Aecidium is known otherwise only from North Carolina and 

 New Jersey on the above host and on A. c(nin(ibinuni L. only from the 

 District of Columbia and North Carolina (according to Schweinitz). 

 It is easily separated from Aecidium ohesum Arth., which occurs on 

 A. Sibiriciim, by the possession of a firm peridium and much smaller 

 aeciospores with thin walls. The latter agrees with A. Cephalanthi 

 Seym, which has been shown by Arthur (Jour. Myc. 12:24. 1906; Mycol. 

 1:236. 1909; 4:19. 1912) to be the aecial form of Puccinia Seymouri- 

 anu Arth. with uredinia and telia on Spartina. 



126. Aecidium Compositarum Authors. 



On Carduaceae: 



Rudbeckia triloba L., Naamans Creek, April 27, 1894, A. Com- 

 mons. 

 This Aecidium like many others on Compositae is doubtless heter- 

 oecious and may belong with telia on some Cyperaceous or Juncaceous 



