1918] 
BURT—CORTICIUMS CAUSING PLANT DISEASES 121 
and in May, 1917, respectively, agree with the collections from 
Venezuela and Colombia in all respects except slight differ- 
ences as to whether the hyphae are hyaline or slightly colored. 
In cross-sections of the leaves of all the specimens, fungous 
hyphae are present more or less abundantly between the cells 
of the leaf parenchyma and extending across the intercellular 
spaces of the leaf. Occasionally these hyphae may be traced 
outward to the under surface of the leaf, where they form a 
part of the layer, one to three hyphae thick, of hyphae run- 
ning along the surface of the leaf, sending out branches at 
nearly a right angle, and forming a membrane about as 
loosely interwoven as the fructification of the common Corti- 
cium vagum. These hyphae range from 44 to 6 д in diameter 
and are neither nodose-septate nor incrusted. In the Porto 
Rican specimens, which have most of their basidia still swollen 
with protoplasm and only occasionally bearing spores, and 
are therefore hardly mature, the hyphae are mostly hya- 
line and show no tinge of color except in the case of those 
hyphae next to the substratum, where local thickenings of 
the fructification occur. In the Ernst collection from Vene- 
zuela the hyphae when stripped from the leaf are of a very 
dilute honey-yellow—the honey-yellow of Ridgway greatly 
diluted. The hyphae of the specimen from Colombia are some- 
times hyaline and sometimes with a slight yellowish tint, be- 
ing about intermediate between the Ernst collections and 
those from Porto Rico. 
Basidia are scattered along the hyphae at right angles to 
the surface of the leaf. But few basidia are present in the 
Ernst specimen, which appears to me to be old, and I did not 
succeed in finding spores in the few preparations which the 
bit of material permitted. Miss Wakefield found the spores 
of this collection to be 9-13344 д. The basidia collapse 
quickly after spore formation. 
Nothing in the nature of appressoria for attachment of the 
fructification to the leaf could be found; the fructification ap- 
pears to be anchored along the under side of the leaf by the 
hyphae from the parasitic intercellular vegetative mycelium, 
