AMERICAN 
JOURNAL OF BOTANY 
Vol. Ill December, 1916 No. 10 
THE UREDINALES FOUND UPON THE ONAGRACEAE 
G. R. BiSBY 
The members of the family Onagraceae, while of cosmopolitan 
distribution, are particularly American. Western North America is 
especially rich in species belonging to this family. Similarly, while 
a few rusts upon members of the Onagraceae are scattered over many 
parts of the world, the majority of them are known only from America. 
The Sydows, in the three published volumes of their Monograph of 
the Uredinales, list 27 species of rusts upon the Onagraceae. Of these, 
15 species are given as existing only in North America, 3 species only 
in South America, and 2 species both in America and in other coun- 
tries. Of the species for which the Americas are not included as 
localities, 3 have been found to be present. Thus, of the 27 species 
listed by the Sydows, 23 occur in the Western Hemisphere, and 21 
of these have been found in North America. In addition to the species 
published in the Sydows' monograph, there are Aecidiiim Anograe 
and Puccinia Fuchsiae, both known only from North America. Puc- 
cinia Veratri, a widely distributed species, has rather recently been 
found to have its aecial stage upon certain of the Onagraceae; the 
telial stage only is listed in Sydow, and not included above. Puccinia 
Nesaeae (Ger.) Ell. & Ev., listed in Sydow as occurring upon Nesaea, 
is misplaced, the host in reality being Ludwigia, a genus of the Ona- 
graceae. 
The family Onagraceae has proved perplexing to the phanero- 
gamic taxonomists; a glance at the lack of uniformity in ideas of 
nomenclature and arrangement of species as represented in various 
floras attests to the uncertainty of specific characters in this group of 
plants. These very uncertainties and variabilities have given this 
family important consideration from an evolutionary standpoint. 
An extensive literature has grown around the genus Oenothera alone. 
[The Journal for November (3: 481-526) was issued Dec. 23, 19 16.] 
527 
