UREDINALES OF GUATEMALA BASED ON COLLECTIONS 
BY E. W. D. HOLWAY 
IV. Puccini A on Carduaceae, Form-genera, and Index 
J. C. Arthur 
The preceding parts of this account of Guatemalan rusts were 
pubHshed in this journal (June, 1918, pp. 325-336; October, 1918, pp. 
1.20-446; November 1918, pp. 462-489). With the present conclud- 
ing part an index both to rusts and hosts is provided to facilitate 
ready reference. 
The composites of the tropics are both numerous and diversified. 
In many of the genera are intergrading forms. The composite rusts 
are also numerous and in many cases most difficult to delimit, often 
showing variations comparable with those of the hosts. The material 
of this part has been reviewed and, when required, critically studied by 
Professor H. S. Jackson, who has drawn up the diagnoses for the eight 
new species. The composite collections of Professor Holway from 
Costa Rica were studied at the same time and the results pubhshed 
in a paper by the writer on the Costa Rican rusts in Mycologia (10: 
111-154. 1918). 
The species here remaining in form-genera are not so numerous as is 
usually the case with tropical rusts. All but two or three of them 
evidently belong to the Aecidiaceae, and the other stages can be ex- 
pected to turn up before very long. 
For this fine showing of Guatemalan rusts chief credit is due to 
Professor E. W. D. Holway, who has given abundantly of his time and 
private means to carry out the explorations, and who has also co-oper- 
ated in the study of the material. Grateful acknowledgment is also 
to be made to the officers and mycologists of the Purdue University 
Agricultural Experiment Station who have provided facihties for 
making the microscopic examinations and have assisted in the studies. 
178. PucciNiA INSULANA (Arth.) Jacks. & Holw. (on Carduaceae). 
Vernonia sp,, Retalhuleu, Feb. 26, 1916, O, IIi, II2, III, 5J7. 
The species has been known heretofore from the West Indian islands 
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