of the Genus Doassansia , Cornu. 31 
D. deformans occurs in all the green portions of the plant ; 
in the petioles and ribs of the leaves ; in the peduncles and 
pedicels of the flower-stalks ; and in the walls of the ovary. 
It produces distortions of all of these parts, some of them of 
very large size. 
When the blade of the leaf is affected, the fungus is con- 
fined to the veins, and the leaf is curled and twisted as if 
suffering .from the attacks of some insect ; the petioles are 
swollen at various points and usually bent at the swollen 
area into a sort of knee. The same thing happens in the 
case of the peduncle. The pedicels enlarge and their natural 
purple colour is often much increased under its influence. 
The affected ovaries may be told by their being swollen 
and projecting two to three times as far from the head of ripe 
fruits as their healthy neighbours. 
A petiole may be swollen, for a length of two or three 
inches, to a diameter of an inch or more. A whole raceme 
may be affected, and one such specimen was inches high 
and inches in diameter, while the peduncle just below was 
only i inch in diameter. The bases of all the leaves of a 
plant are at times swollen to a mass 6 to 8 inches across. 
So large are most of the distortions caused by this species 
that it seems strange that it has not been reported before ; 
but the fact is that, in spite of the deformities produced by it, 
it is not very noticeable, and resembles rather the work of 
insects than of a fungus. 
The structure of the petioles and peduncles of Sagittaria 
variabilis- has been noticed before in connection with the 
description of D. obscnra. From top to bottom of these 
portions run cylindrical spaces which are divided into short 
cylinders by frequent partitions at regular intervals. It is in 
these short spaces that the slender mycelium of the fungus, 
clinging closely to the bounding cell, forms a dense network. 
The sori fill the spaces in crowds, and forcing apart the 
walls, cause each space to enlarge to several times its normal 
diameter. It is in this way that the distortion is produced. 
In the leaves and ovaries, the spaces are smaller and the 
