March 1905] Cultures of Urcdiucac in 1904. * 63 



were mentioned as bearing teleutospores a year ago, and stand- 

 ing near aecidinm-laden bushes of Dirca palustris. Last year's 

 supposed results, which were based on a single sowing of 

 aecidiospores, can be explained by supposing that the Bromus 

 plants were already infected when brought into the laboratory. 

 The above plentiful data show no escape from the conclusion 

 that the common Bromus rust belongs to the aecidium on 

 Clematis Virginiana, and not to the aecidium on Dirca palus- 

 tris. The name Piiccinia hydnoidea (B. & C.) Arth., therefore, 

 does not belong to the Bromus rust, but to some teleutosporic 

 form not yet identified. The descriptions of uredospores and 

 teleutospores given at the place cited belong to Piiccinia to mi- 

 para Trel. 



There are at least three species of aecidia found upon Cle- 

 matis in the United States. Aecidium occidentale Arth. occurs 

 on C. Douglasii in the northwestern region; its teleutosporic 

 connection is not known. Aecidium Clematidis DC, found on 

 C ligusticifolia, C. Scottii, C. Fremontii, C. Drummondii, C. 

 lasiautha and C. Viorna, ranging from Iowa to Montana and 

 southwestward to the Pacific coast, is the first stage of Puc- 

 cinnia Agropyri E. & E. The third species is Aecidium Cle- 

 matitis Schw., the one under consideration, found on C. Vir- 

 giniana, ranging throughout the United States and Canada east 

 of the Rocky mountains, and belongs to Piiccinia tomipara Trel. 

 It has larger spermogonia, and somewhat smaller aecidia and 

 aecidiospores than that of P. Agropyri. It may be characterized 

 as follows : 



Aecidium Clematitis Schw. 



0. Spermogonia epiphyllous, in small groups, honey-yellow, puncti- 

 form, subepidermal, globose, 90-140 /* in diameter ; ostiolar filaments 

 40-60 t* long. 



1. Aecidia hypophyllous, in orbicular groups, crowded ; peridia low, 

 margin somewhat revolute, erose; aecidiospores globoid, 16-22 by 18-26 

 M, wall rather thin, 2 v, colorless, minutely vcrrucose. 



The teleutospores used in the cultures were all of the nor- 

 mal two-celled form. The original collection on which the name 

 was based does not appear to differ in any appreciable way from 

 the usual two-celled form except in the many-celled teleutospores, 

 which appear to be variations not uncommon in many grass 

 species. The hosts of all three collections used in the cultures 

 were of the form often made a distinct species under the name 

 Bromus purgans L., which differs but slightly, chiefly in pubes- 

 cence, from the typical B. cilia tus. 



3. Puccinia Stipae Arth. On May 9, 1903, I found 

 at Spirit Lake, Iowa, spermogonia and young aecidia on leaves 

 near the ground of Aster multiilorus, with germinated teleuto- 

 spores on old leaves of Stipa spartea within a few feet, and no 

 other grass or sedge rust noticeable for a considerable distance 



