Arthur: Uredinales of Porto Rico 
169 
The 650 collections distribute themselves under 109 species of 
rusts, giving an average of about 6 collections to each species. 
Actual duplicates in the set are few, however. The several num- 
bers under each species are often required for additional hosts, 
over I/O species altogether being represented, many not hereto- 
fore recorded as such, for illustrating successive stages of the 
fungus, some before unknown, and for distribution, over 65 
localities having been visited. 
The species previously known from Porto Rico do not exceed 
thirty-five in number, or about one third of the number secured 
by Dr. Stevens. The richness of Dr. Stevens’ set is also attested 
by showing thirty-nine species, or over one third of his collection, 
as additions to the previously known rust flora of North America, 
of which number eighteen are new to science. 
The family Coleosporiaceae is represented in Porto Rico by 
three species, of which Coleosporhim Plumierae is distinctly 
West Indian. It is not, however, certain that this species is 
entirely autonomous, it may well be only a race of some earlier 
described species of wide range. Only cultures will fully eluci- 
date this point. It is significant that no member of the genus 
Finns occurs in Porto Rico. So far as known the species of 
Coleosporhim form their aecia only on leaves of pines. It is 
practically certain that the three species in Porto Rico maintain 
themselves by the uredinial repeating spores, and are not indigen- 
ous to the island. 
The family Uredinaceae, often called Melampsoraceae, is some- 
what better represented. Five species are listed here. Two of 
these (under Kuehneola) have heretofore been invariably placed 
with the next family. The shift is made on account of the 
catenulate teliospores, in contradistinction to simple teliospores 
with one or more cells, and the resemblance of the uredinial 
sorus to that of Pucciniastrum in the manner of spore formation. 
The species of the family are like those of the preceding family 
in maintaining themselves by the uredinial repeating spores, only 
one, Cerotelium Canavaliae, being known to produce telia in 
the West Indies, and for none of them is the aecial condition 
known. There are five other forms listed under the form-genus 
