﻿112 BOTANICAL GAZETTE [February 



the morphology of one species, and Cunningham^ worked on 

 the life histories of two species. Duggar^ investigated the ger- 

 mination of the teleutospores. In 1894 DieteH published his 

 excellent monograph of the genus. This included all the Ravene- 

 lias then known and gave a brief resume of previous work, together 

 with a rather full discussion of the characters of the various 

 species, followed by systematic descriptions and plates to illus- 

 trate the various species. Since then many new species (about 

 fifteen) have been described by various authors, most of them 

 from the Americas. Much light was thrown on the general life- 

 history, morphology, etc., by these investigations, and the true 

 status of the genus was fully determined, all of its characters 

 undoubtedly placing it with the Uredineae. Much careful work 

 yet remains to be done, as all that is known of most of the species 

 is a brief systematic description of the dried plant. 



The writer is under many obligations for specimens, etc., to 

 Mr. E. VV. D. Holway, Dr. P. Sydow, Dr. P. Hennings, Dr. P. 

 Dietel, Dr. W. G. Farlow, Professor E. O, Wooton, Mr. S, B. 

 Parish, Mr. Elam Bartholomew, Dr. D. Griffiths, Shaw Botanical 

 Gardens, New York Botanical Gardens, Dr. J, C. Arthur, and the 

 U. S. Dept. of Agriculture ; also to Professor George F, Atkinson 

 for his aid and advice throughout the prosecution of this work. 



All drawings were made with the aid of an Abbe camera 

 lucida from material that had been boiled in lactic acid to restore 

 the spores to their natural size and shape and bring out details 

 that would not otherwise be noted. In some instances only a 

 small quantity of material of a given species was available. In 

 such a case the question arose how best to utilize this to show all 

 the essential characters. The method pursued was first to mount 

 a bit in distilled water and allow the water to evaporate. In this 

 condition all the minute surface markings of the spores are more 

 plainly seen; but this preparation would not show the germ pores 

 and would usually burst the cysts. Hence a second mount was 



«• Notes on the life history of Ravenelia sessilis B. 3.xid^ Raven elia stictica B. and Br. 

 Scientific Mem. of Medical Officers of the Army of India, 1889. 



3 Germination of the teleutospores of Ravenelia cassiaecola. Box. Gaz. 17: 144- 

 148. 1892. 



^ Die Gattung Ravenelia. Hedwigia 33 : 22-69, 367-371. 1894. 



