Arthur and Holway: VIOLET RUSTS OF NORTH AMERICA. 633 
occurs in open woodlands from the last of March to the begin- 
ning of June, but is rather infrequent and local. It is distin- 
gished from the ecidium of Pucczntza Viole by the markedly 
smaller cups and spores, and by a greater tendency to form 
small, round groups seated on the mesophyll of the blade, 
rather than on the midrib or veins. The peridium is usually 
conspicuously white; the cylindrical elongation noted in the 
description by Berkeley and Curtis is occasionally to be seen, 
but must be considered as accidental, depending upon condi- 
tions of growth. The same kind of development is met with 
in other forms of acidia (see notes on “ccdium pulcherrimum 
Rav. in Bull. Lab. Nat. Hist. of Univ. lowa 4: 399-400). 
Examination of specimens in the Schweinitz collection at the 
herbarium of the Philadelphia Academy of Sciences shows that 
both species which he described as new, occurring on Vola 
pedata and V. sagittata respectively, belong here. The name 
coming first on the page is taken as the authentic name of the 
species. The Schweinitz specimens on both hosts are ample, 
but neither shows the ecidia in so characteristic a form as does 
the specimen in the same collection on Vola obliqua, which 
Schweinitz referred to 4czdium Violarum. The last has very 
small, compactly clustered zcidial cups, in small round groups, 
while both the former have the cups somewhat larger, and 
sparsely scattered or solitary. The difference in habit is doubt- 
less due to the influence of the host and the atmospheric con- 
ditions affecting the development, in part, combined with the 
accidental distribution of the infection over the leaf surface. 
Spermogonia have not been seen by.the writers, but Burrill 
(Par. Fung. Ill., p. 223) states that they precede the ecidia, al- 
though he does not describe them. 
Puccinia Viole (Scuum.) DC. 1815. Flore Francaise 6: 62. 
SYN. : 
1803. czdium Viole Scuum. FI. Sell. 2: 224. 
1803. Uredo Viole Scuum. FI. Sell. 2: 233. 
1805. 4czdium Violarum DC. FI. Franc. 2: 240. 
1825. Puccinia Violarum Linx. Sp. Plant. 2: 80. 
1875. Puccinia hastate CooKE, Grev. 3: 179. 
1888. Puccinia Fergussont hastate DET. Sacc. Syll. 
Fung. 7: 682. 
1897. Puccinia densa D. & H. Hedw. 26: 208. 
1898. Diceoma Viole KuNTZE, Rev. Gen. Pl. 3: 471. 
