86 
IOWA ACADEMY OF SCIENCE 
The accompanying notes on the Peronosporales during the past collecting 
season are based on observations made from early spring to late autumn at 
various localities. The season up to July 17th was spent in New York City and 
consequently few observations were made. The 18th and 19th of July were 
spent in the vicinity of Newark, Delaware, where short collecting trips were 
made each day. The remainder of the summer months were spent in central 
Indiana, the collections being made chiefly in Hamilton, Madison, Marion and 
Putnam counties. After arriving in Fayette in early September, but few obser- 
vations were possible, as other matters made such demands as to leave but little 
leisure. 
During the collecting season seventy-two specimens were collected and exam- 
ined. Of these eight, or one in nine, contained oospores. Of the species repre- 
sented a few were observed under conditions which prevented any conclusion 
as to their distribution through the season, while most of them showed marked 
seasonal development. Plasmopara pygmaea was observed only as an early 
spring form; Albugo portulacae, A. tragopogonis, RhysotUeca Halstedii, Peronos- 
pora effusa, and P. polygoni appeared during the latter part of the summer and 
autumn; Bremia lactucae, Peronospora euphorbiae, and P. potentillae appeared 
to be early summer forms. The remaining species, when observed more than 
once, appear to flourish throughout the season. 
The abnormally cold spring and summer need no further comment than the 
following data from the United States Weather Bureau: 
METEOROLOGICAL DATA FOR 1907. 
Months 
New York, N. Y. 
Newark, Del. 
Indianapolis, 
Ind. 
Fayette, Iowa 
Rain 
Dept. 
Rain 
Dept. 
Rain 
Dept. 
Rain 
Dept. 
March 
3.89 
—0.19 
2.62 
—1.22 
4.07 
+0.48 
1.33 
-0.93 
April 
3.89 
+0.51 
3.23 
—9.16 
2.07 
—1.66 
1.03 
—2.17 
May 
4.08 
+0.90 
4.98 
+1.09 
2.85 
—1.28 
2.34 
-2.50 
June 
3.29 
+0.16 
5.72 
+2.11 
4.68 
+0.37 
6.99 
+1.14 
July 
1.18 
—3.36 
2.95 
—1.39 
4.41 
+0.28 
Aug 
2.48 
-2.05 
3.35 
—1.01 
2.33 
—1.00 
4.18 
+1.28 
Sept 
8.00 
+4.41 
8.06 
+4.08 
2.31 
-0.74 
3.58 
+0.62 
Months 
ft 
B 
ft 
a 
a 
ft 
ft 
a 
ft 
a 
a 
ft 
a> 
<v 
CD 
(V 
O) 
<v 
o 
(D 
P 
Eh 
P 
H 
P 
Eh 
P 
March 
40.8 
+3.3 
43.6 
+3.0 
48.0 
+8.4 
37.6 
+7.4 
April 
45.0 
—3.1 
47.2 
—3.2 
43.3 
—9.1 
39.9 
—7.3 
May 
55.3 
—4.0 
57.4 
—4.5 
56.8 
-6.5 
51.0 
-6.7 
June 
66.2 
-2.3 
65.2 
-4.5 
68.0 
-4.4 
64.3 
—3.9 
July 
74.9 
+1.3 
74.6 
—0.5 
75.1 
—1.1 
71.6 
-0.7 
Aug... 
72.0 
-0.2 
71.2 
—2.1 
72.4 
-1.2 
67.8 
-1.7 
Sept 
67.8 
+1.3 
68.2 
-1.0 
65.8 
—0.9 
59.7 
-2.8 
Last frost of spring 
April 21 
May 12 
April 21 
May 27 
First frost of 
autumn 
November 12 
October 22 
October 21 
September 22 
