AMERICAN UREDINE^E. 305 



III. Sori sparingly on leaf - blades, more commonly on 

 sheaths, culms and inflorescence, linear, often confluent, black, 

 early naked, ruptured epidermis noticeable; teleutospores ob- 

 long-fusiform, oblong-cuneiform, or narrow obovate, 35-60 x 

 12-22 u, golden-brown, smooth, somewhat constricted in the 

 middle: apex darker colored, considerably thickened, obtuse 

 or rounded; base narrowed; pedicel usually barely as long as 

 the spore, firm, colored like the spore. 



Among the most common of rusts, although by no means 

 so abundant and inclusive as has been assumed up to within 

 the last few years. It is much less common upon the leaf 

 blades than are other species of rusts, but is frequentl} r seen 

 upon the culms and sheaths, forming conspicuous black, 

 effused patches. The form of the uredospores and the num- 

 ber and arrangement of the pores are characteristic, and readily 

 distinguish the species from some others that are most likely 

 to be confounded with it. The uredospores when fresh have 

 a decidedly brownish color, quite unlike the clear orange 

 yellow of those of Puccitiia rhamni and P. rubigo-vera. 



The connection of the aecidium upon barberry, as one of 

 the stages in the life cycle of the rust, is one of the best estab- 

 lished facts in the biology of the UredinecR. As there is always 

 a possibility that the conclusions drawn from work done upon 

 European material may not be applicable to what are assumed 

 to be the same species in America, it is worth while to mention 

 that the connection in this case has also been established with 

 American material. In the spring of 1889 H. L. Bolley, 

 working in the botanical laboratory of Purdue University, 

 sowed sporidia from germinating teleutospores from wheat 

 upon the leaves of the common barberry, and as a consequence 

 secured aecidia; this was successfully repeated several times. 

 Other American botanists have undoubtedly made cultures, of 

 which the most extensive are probably those of M. A. Carle- 

 ton, whose results are now in process of publication by the 

 U. S. Department of Agriculture, as part of the work of the 

 Division of Veg. Physiology and Pathologv. 



In making up the present fascicle only forms have been 



