TO Witson: NortH AMERICAN PERONOSPORALES 
American Fungi 780g were examined. Berlese had previously * 
cited this as authentic material of the thin-walled species, but it 
proved to be the most pronouncedly thick-walled specimen at hand. 
In a conidium of 12 » diameter the thickening frequently reaches 
5 # making the connecting strand of protoplasm but 2 yp. 
The results of the morphological investigations of Stevens,f 
coupled with markings and general development of the epispore of 
the odspore, lead to the conclusion that Zalewski was correct in his 
placing of the species. That the relationship of this species should 
long be in doubt is not surprising, as the odspores which are 
borne in large galls on the stems of the host escaped notice until 
recently, while the conidia on the majority of hosts bear a super 
ficial resemblance to those A. 7) ragopogonis. In all the material 
examined the conidia are short-cylindric, appearing in certain 
planes almost cubical, except in the case of those on /pomoea 
Batatas, the sweet potato, which are very much more rounded 
than typically. It is not impossible that a distinct species occurs 
in this host. 
On CONVOLVULACEAE: 
Calonyction aculeatum (L.) House, Florida, Britton 419; 
Oaxaca, Holway 3735. 
Convolvulus incanus Vahl, Texas, Heller 1910. 
Ipomoea Batatas (L.) Lam., Alabama, Earle 2265 ; Delaware, 
Chester ; Louisiana, Langlois (N. Am. Fungi 780g) ; Mis- 
sissippi, Earle (Econ. Fungi 47); New Jersey, Arthur, 
Edis (N. Am. Fungi 205), Stevens ; South Carolina, 
Ravenel (Myc. Univ. 875), Roifs 1685 ; Porto Rico, Under- 
wood & Griggs 8. 
Ipomoea carolina Pursh, Louisiana, Langlois 598 ; South 
Carolina, Ro/fs. 
Ipomoea lacunosa L., > Kansas, Swingle; North Carolina, 
coll, irn, 
Ipomoea leptophylla Torr., Kansas, * Bartholomew (Fung! 
Columb. 2003). 
Ipomoea mexicana A. Gray, New Mexico, Mulford 920; Mex- 
_ ico (city), Pringle 6607. ee 
* Icon. Fung. Phyc. 7. 1898. 
T Bot. Gaz. 38: 300-302. f. 7, 2. 1904. 
