14 
ling or lacerated into many short erect or slightly reflexed segments. 
Peridial cells, below small and polygonal, above very large and having 
a flattened conical portion projecting outward and upward from the in¬ 
ner side, sometimes containing a few yellow granules, 18-42 by 15-3G//, 
wall 2-5// thick, conspicuously tuberculate, the warts forming short 
lines or clusters on the surface. Spores yellow or at length pallid, sub- 
globose or oval, regular or slightly angular, 23-32 by 18-25//, mostly 
24-28 by 21-24//, wall 2-4// thick, marked with both very fine warts and 
short, very blunt, round tubercules 1-2// in diameter, which are wanting- 
on the two attached surfaces but extend around the spore in a band, be¬ 
coming closely crowded midway between the attached surfaces. Sper- 
mogonia amphigenous, scattered, immersed, globose or flask shaped, 
about 100// in diameter, scarcely visible except in section. 
On Dalea laxijiora. Rockport, Eooks County, Kans., June 12, 1888, 
E. Bartholomew, No. 228. 
This is a peculiar and well-marked species. The upper peridial cells 
on the inner surface overlap somewhat like the scales of a fish, but also 
project outward. They are also remarkable for their great size. When 
the secidia occur on the petioles they cause an enlargement, but on the 
leaflets scarcely any thickening can be observed. Mr. Bartholomew re¬ 
marks that the species is u very abundant, making many of the host 
plants eutirely abortive.” 
A STUDY OF THE ABNORMAL STRUCTURES INDUCED BY USTI- 
LAGO ZEiE MAYS . 1 
(Plates II, III, IV, V, YI, VII.) 
By Etta L. Knowles. 
The fungus known as Ustilago Zece Mays is found on Indian corn 
everywhere. It appears in stem, leaf, grain, and in both staminate and 
pistilate flowers, producing an abnormal growth of tissue sometimes as 
large as a man’s fist, whitish at first but black when the spores ripen, 
which is about the time of the ripening of the corn. 
In order to understand the changes which are produced by the j’ungus, 
a careful study was at first made of the normal structures. Alcoholic 
material gathered July 19, 1887, was used for this purpose and also for 
the study of the abnormal structures. Schulze’s solution was used 
for staining the sections and glycerine for mounting them. The draw¬ 
ings were all made with a camera and are on the same scale. 
Upon examining the stem it was found to consist of an epidermal 
system and scattered fibro-vascular bundles, of a somewhat oval form 
in cross section, between which were the rather large cells of the ground 
1 This work was carried on under the direction of Prof. V. M. Spalding, in the bo¬ 
tanical laboratory of the University of Michigan, 1888. 
