280 
two-celled, irregular in shape, broadly ovate to subelliptical or fusiform, bluntly 
rounded or slightly tapering toward the apex, symmetrical or often slightly bent. 
Average dimensions 55 by 25//. Promycelia several, not uncommonly proceeding 
from either extremity. Pedicels when young often more or less inflated below the 
spore. Mycelium perennial in leaves, branches, or trunks of Juniper us virginiana, 
very commonly inducing a “ bird’s-nest ” distortion. 
lloestelia stage .—Spermogonia yellowish orange, preceding the aecidia by about ten 
days. iEcidia liypopliyllous or more commonly on petioles and young shoots, and 
especially on young fruit, densely clustered, brown, at first subulate, then fimbriate; 
the peridia splitting to the base, with its divisions slightly divergent. Peridial cells 
rather slender, the ridges somewhat prominent, sublabyrinthiform, horizontal or be¬ 
coming inwardly oblique towards the extremities. Average measurements (towards 
the apex of the peridia) 7 by 18//. JEcidiospores smooth, spherical or irregularly 
oval to oblong; average diameter 25//. 
Mycelium annual in the leaves of Cydonia (quince) and in leaves, stems, and fruit 
of Amelancliier canadensis (service berry) in June. 
Oospora scabies Thaxtcr. 
Ann. Rep’t. Conu. Agr. Exp. Sta., 1891, p. 159. 
Vegetative hyplise hyaline or brownish from the general discoloration of the sub¬ 
stratum, .4-.0//, rarely as much as 1// in diameter, curving irregularly, septate or pseu- 
doseptate, branching. Aerial hyplne at first white, then grayish, evanescent, break¬ 
ing up into bacteria-like segments after producing terminal spirillum-like “ spores” 
by the coiling of their free extremities. Forming a firm, lichenoid pellicle on 
nutrient jelly, and usually when growing in contact with the air producing a deep 
black-brown discoloration ol the substratum. Producing the disease known as 
“Scab” on potato tubers and a similar affection of beet roots. 
The measurements of the hyplne of this form given in the original 
description (.6-1//) are somewhat larger than they should be, hyplne 1// 
in diameter being very rarely seen and the average diameter being 
usually less than .6/v. The spiral forms are most readily seen in the 
grayish film developed naturally on the scab spots, though they are ob¬ 
tained without difficulty from the aerial hyplne on hard agar cultures. 
The writer has seen no published account of further European obser¬ 
vations upon the disease, and such accounts are to be awaited with in¬ 
terest. Sauvageau,* however, has apparently obtained the scab fungus 
accidentally from water, and described it as Oospora metchnikowi n. s. 
Although this writer does not mention the spiral “spores” the form 
corresponds so closely to the present species, both in structure and in 
its effects upon the substratum, that the identity of the two seems 
more than probable. 
* Ann. d. Plnst. Pasteur, t. vi, p. 242. 
