170 Robinson. — Notes on the Genus Tciphrina: 
confined to roundish blotches, but these soon become irregularly 
confluent and cover much or all of the surface of the leaflet. 
Microscopically, the most noticeable modification in the in- 
fected parts of the leaf is the very compact and palisade-like 
structure which the spongy parenchyma and epidermis assume. 
The asci are formed on both sides of the leaf, and reach 
maturity late in June or early in July. They are 24-32 /x long, 
and somewhat dumb-bell shaped in outline, being constricted 
in the middle apparently by the cuticle of the host ; the 
thickness of the exserted portion is 9-14 jx, of the constricted 
part 6-11 /x, and of the broad base 9-21 /x. In size and shape 
the asci closely resemble those of the European Exoascus 
Carpini , Rostrup ; from that species however this form on 
Rhus is well distinguished by the presence of a mycelium 
which penetrates the inner tissues of the host-leaf. From 
T. deformans , of which it was once classed as a variety, 
T. pnrpurascens differs not only in the size and form of its 
asci but in having no stalk-cells. The spores are eight in 
number and ellipsoidal in form ; their maximum diameter 
is 3I—5 /x and minimum 2i~4 Like the spores of other 
species they are very liable to division while still in the 
ascus. 
The first notice of this form is in ‘ Notes on the Third and 
Eleventh Centuries of Ellis’s North American Fungi’ 1 by 
Dr. Farlow, who gave a partial description of specimens 
found at Dartmouth, Mass., by Dr. B. D. Halsted. It as 
there considered as possibly a variety of Exoascus deformans 
or, at least, a related species. Mention was made of a similar 
form on an African Rhus described by Magnus, as the writer 
believed, although he could not at the time recollect where 
it was published. I have since been informed by Dr. Farlow 
that he was in error, and that the description which he had 
in mind was by Dr. F. Thomas instead of Magnus. In the 
article, published in 1 883 2 , Thomas describes a deformation of 
1 Proceedings of the Amer. Acad., vol. xviii (1883), p. 85. 
2 Beiichte der Deutschen botanische Gesellschaft, Bd. i (1883), Berlin. 
