48 
E. W. OLIVE AND H. H. WHETZEL 
hymenium which arises just under the epidermis, without peridium; 
tehospores uninucleate, borne singly at the end of pedicels which 
arise from a binucleate mycelium, 13-14 by 18-24 jjl, thin-walled, oval, 
with a rounded apical protuberance, germinating apically at maturity 
to produce each a long, cross-septate basidium (promycelium) bearing 
4 basidiospores (sporidia), similar in shape to the tehospores and 8 by 
11-12^1. 
Vegetative mycelium composed of coarse intercellular hyphae, 
made up of binucleate cells, some of which send large botryose, or 
irregularly shaped, haustoria into adjacent cells. 
On Hippocrateaceae : 
Hippocratea voluhilis L., Porto Rico (W. & O. No. 87, type ; figs. 1,2). 
It would indeed be peculiar if this conspicuous fungus had entirely 
escaped description. We are, however, unable to find any published 
matter pertaining to it. It is, perhaps, not so strange that it has 
escaped inclusion in the rusts. In the collections at the Agricultural 
Experiment Station at Rio Piedras we found it classed as an insect gall ; 
really quite a logical place for an old specimen, when judged alone 
from its gross appearance. 
As is well known, many tropical rusts are pale and inconspicuous 
and otherwise quite unlike the yellowish or brownish rusts with which 
we are familiar in colder climates; further, according to Professor 
Arthur, ''all of the so-called species of Eriosporangium and Argomyces 
are white-spored, as well as the uredinia of Uredinopsis and many 
others." And he adds: "I see no reason why this is not a true rust, 
although a very unusual one."^ 
It is, indeed, quite likely that the coarse mycelial hyphae and 
the remarkable botryose haustoria will prove to be unusual features 
among rusts ; and that these are characters which are doubtlcvss more 
prevalent among smuts than among rusts. But, on the other hand, 
the spores are cut off externally, much as in Uromyces, from the ends 
of protruding hyphae; and, further, the spore-bearing hyphae are 
always produced in a more or less regular, superficial hymenial layer, 
which arises in hypodermal regions, generally just under the epidermis. 
The latter are undoubtedly rust characteristics and not those of smuts. 
It is of considerable interest, indeed, to find in this form characters 
common to both smuts and rusts, thus adding emphasis to the general 
6 In letter of October 6, 1916. 
