1918] JACKSON—PUCCINIA 205 
or fusiform, 16-22 by 56-80 y, narrowed at both ends, apex obtuse, 
not thickened, slightly constricted, wall cinnamon brown, thin, 
I-1.5 4, smooth, pedicel colorless, fragile, equaling the spore in 
length or usually shorter. 
On Vernonia Schiedeana Less., Guatemala City, Guatemala, February 8, 
1917, Holway 841, February 15, 1916, O, I, II, III, Holway 494; Chinautla, 
Guatemala, February 12, 1916, O, I, II, III, Holway 480; Moran, Dept. 
Amititlan, Guatemala, December 22, 1916, I, II, III, Holway 621; Cordoba, 
Vera Cruz, Mexico, January 27, 1895, O, I, II, III, Pringle 6080, from specimen 
in the phanerogamic herbarium of the New York Botanical Garden; Jalapa, 
Vera Cruz, Mexico, October 2, 1898, I, II, III, Holway 3111 (type of Dietelia 
Vernoniae Arth.). 
In the course of the study of these collections it was at first thought that 
some of the specimens represented a mixture of Endophyllum Vernoniae and 
Argomyces Vernoniae (cf. 7), the aecia agreeing in morphology with the former 
and the uredinia and telia closely resembling the latter. A most careful 
examination, however, failed to reveal the presence of pycnia associated with 
the uredinia in any of the collections, and a re-examination of the type of 
Endophylium Vernoniae showed a few telial sori and a few urediniospores which 
agree with those of the other collections. All of the collections cited show all 
spore stages of the rust and the association cannot be interpreted as accidental. 
The rust, according to this interpretation, is of the Eriosporangium type, 
possibly a correlated form with Argomyces Vernoniae. It is evidently closely 
related to the two preceding, differing, however, in the absence of a typical 
peridium in the aecia. 
The Cordoba collection differs from the Guatemalan material in the some- 
what broader teliospores, a greater proportion of which are shorter than the 
maximum measurements given. The aecia are usually solitary and occur on 
noticeably thickened areas rather than on yellowish spots as in most of the 
Guatemalan collections. The material is scanty, however, and the leaves are 
evidently from a more mature, less vigorously growing specimen of the host 
than the other collections. 
4. Puccinia Arthuriana, nom. nov.—Argomyces Vernoniae 
Arth. N. Am. Flora 7:218. 1912, not P. Vernoniae Schw. 1832. 
On Vernonia arbuscula Less., II, Pineland, Long Bay Cays Section, Andros, 
Bahamas, January 20-22, 1910, J. K. Small and J. J. Carter 8613; Vernonia 
bahamensis Griseb., II, III, North Caicos, Bellemont and vicinity, Bahamas, 
March 2, rorr, C. F. and C. M. Millspaugh 9175; I, Whiteland, Tenados, 
Inagua, Bahamas, October 28, 1904, G. V. Nash and N. Taylor 1344; II, 
Hanna Hill, Long Cay, Bahamas, December 7-17, 1905, L. C. K. Brace 4020; 
Vernonia canescens H.B.K., II, UI, Volcan de Irazu, Cartago, Costa Rica, 
