466 
IOWA ACADEMY OF SCIENCE Vol. XXIV, 1917 
under T. pratense are those of Davis and Johnson, who connected 
this stage with the life cycle of rust on red clover. See report of 
the National Association for the Advancement of Science, De- 
cember, 1916 : The Aecial Stage of Red Clover Rust by Davis 
and Johnson. 
TABLE II. 
Peridial Cells— Stage 1 Aecia 
Hosts 
Sydow 
.8, p.161 1 
Ivanhoff 
Davis 
High 
Wide 
Open- 
ing 
No 
Wall 
Wall 
Lumen 
Wall 
Lumen 
2* 
1.5 
1.7-3 
8-12 x 
T. repens 
4-5 1 
4.5 
13.5 
5 
20-22 
308 
230 
310 
10 
23-3.5 
8-10 x 
T. pratense 
5-6.8 
12-16 
189 
178 
224 
5 
. /-1.5 
8-12 x 
T. hybridum 
2.5-35 
10-14 
182 
172 
140 
10 
*Thickness of the inner wall of the peridial cells. 
tThickness of the outer wall of the peridial cells. 
The heading “number” refers to the number of aecial cups 
measured. The measurements were made from stained slides. 
