24 BOTANICAL GAZETTE. 
Notes on the North American Forms of Podosphera. 
BY F, S. EARLE. 
I have lately examined a number of specimens of this genus, 
from different localities and on different host plants, with a view 
of trying to determine their specific relations. 
: Ithough quite a marked difference may be observed between 
perithecia taken from the same leaf, specimens on the same host 
plant from different localities resemble each other quite closely, 
and these forms may be characterized as follows : 
1. Form on Prunus Cerasus. 
2. Form on Prunus Americana. 
(One specimen, Dixon, III.) 
Amphigenous, fruiting below; perithecia .0025 in. to .00325 
in.; appendages few, about 6 or 8, placed irregularly, but some- 
times ascending nearly parallel, 14 to 2 times the diameter, 4 or 
5 times parted, tips not much swollen, 
3. Form on Amelanchier Canadensis. 
(Two specimens from Massachusetts and Connecticut. Coll. A. B. Seymour.) 
Amphigenous, or epiphyllous ; perithecia .00275 in. to .00325 
in.; appendages 8 to 16, 2 to 3 times the diameter, much as in 
tke form on Prunus Cerasus, but rather darker and less variable, 
, tips swollen. ' 
4. Form on Spirwa tomentosa. 
(Two specimens, Massachusetts. Coll. A. B. Seymour.) 
Amphigenons, fruiting both sides of leaf or more abundantly 
above ; perithecia small, .0025 in. to .00325 in. ; appendages nu- 
merous, 12 to 24, radiating from all parts of the upper surface, 
1 a times the diameter, 3 to 5 times parted, tips only slightly 
swollen. 
5. Form on Crategus— 
(Three specimens from Illinois.) 
