PLATE I « 
Photomicrographs of spores caught on slides at various altitudes. 
A. —Cluster of Ustilago chlamydospores (3,000 feet, near Wahoo, Nebr., July 16). 
B. —Teliospore, Tilletia tritici spore, three rust urediniospores, and an Altemaria 
spore (1,500 feet, near Wahoo, Nebr., July 19). 
C. —Helminthosporium spore (10,000 feet, Pine Bluff, Wyo., July 19). 
D. —Chain of two Altemaria spores (1,000 feet, between North Platte and Gothen¬ 
burg, Nebr., July 15). 
E. —^Altemaria spore, leaf rust urediniospore, and a stem mst urediniospore (2,000 
feet, near Fort Crook, Nebr., July 22). 
F. —Helminthosporium spore (1,500 feet, near Wahoo, Nebr., July 19). 
G. —Urediniospore of stem rust, two Altemaria spores, and a Cladosporium spore 
(10,500 feet, near Fort Crook, Nebr., July 22). 
H. —Cluster of mst urediniospores and one Altemaria spore (4,000 feet, between 
David City and Grand Island, Nebr., July 13). 
I. —Altemaria spore and stem mst urediniospore (10,500 feet, near Fort Crook, 
Nebr., July 22). 
J. —^Two Altemaria spores and a Cladosporium spore (10,000 feet, near Pine Bluffs, 
Wyo., July 19). 
K. —Scolecotrichum (?) spore (3,000 feet, near Wahoo, Nebr., July 16). 
L. —Fusarium spore (10,500 feet, near Fort Crook, Nebr., July 22). 
M. —Budding spores or sporidia, exact identity unknown (3,000 feet, betv^een 
Meade and David City, Nebr., July 13). 
a Taken with the followins: CQmbinations: A, K, and M, with Zeiss microscope No. 47303.18 oc. and 8 mm. 
objective; E, with Leitz microscope No. 161086, 7.5 oc. and 6 mm. objective; remaining figures with Zeiss 
microscope No. 47303,10 oc. and 8 mm. objective. 
