350 BOTANICAL GAZETTE 
DATA FROM THE EXPERIMENTS 
[MAY 
Response Osmotic Acidity of 
Source of water and nature of vegetation of pressure water 
Stigeo- of water, in terms of 
clonium | mm.of Hg| normal acid 
Drained swamps of Hackensack River, N. J. (river swamps)— 
Average of six samples F—4P 50 0.00192 
Maximum of six samples.........-+-+-seeeeeeeeeeeeeeeeee| teers os 0.0042 
Ce or gt i) 2 a en eee earn rr aoe ua 0.001 
New York City supply, Croton and Bronx Rivers | ge 50 0.0005 
Chicago City supply, Lake Michigan. ...... 205 <sic0-eccweorence F—F 100 Always alkaline, 
: (see fig. 1) about 0.0015 
Grand River; Grand Rapide; Michi ic. od cca cee ceccnesieg nor EF—F 100 As last, or more 
ne 
Aetna, Ind. (Rhus vernix, ra)— 
Average of three samples pressed from black peat.......-...- F—4P feo, =| *hssmrenee 
Miller me , Rhus vernix)— 
Average of two samples pressed from black pea F—4P 50 0.0003 
Oconomowoc, Wis.* (typical Larix swamp), ditch............. F—P 200 0.0004 
Stewart ~— e, Ill., average of three samples pressed from black ce 
— Iso 0.0002 
Ann Arbor, Mich} ; 
First Sister Lake bog (Larix, Chamaedaphne, Sphagnum)— 
Sample A F—P 50 0.0033 
72.2 
ised e aoe. Chamaedaphne, Potentilla palus- 
Sample A PP 100 0.0026 
Sample P—P 150 0.0024 
1 R: , (see fg. 3) 
Tom’s River, N, J. (Chamaecyparis, Sphagnum, Chamaedaphne, 
Sarracenia, Oxycoccus)— 
Sample \, pressed from Sphagnum F—F 170 0.0004 
Sample B, beneath Sphagnum ep 140 0.00048 
Sample C, pressed from black peat rp go 0.0003 
Sample D, margin of pond Fop 40 0.0003 
Ree ee Say eee 
, , N.Y. (Alnus, Eri , Spha, 
Sample A, edge of pond ( eee, Semekeae:) F—P 0.0015 
Sample B, decayed leaves F—}P 110 0.0022 
Sample C, ditch F—F 90 ° 
Sample D, pressed from Sphagnum F— 100 -OO1 
* This water was obtained for me by Dr. H. C. Cow es of this laboratory. 
+ The samples from Ann Arbor weré obtained for me by Dr. H. N. TRaNsEAv, of Alma College, Mich. 
form persisted without the production of palmella at all. The char- 
acteristic forms of this plant in three different waters are shown 1n 
jigs. 1,2, and 3, which are to be compared with previously published 
figures, and are self-explanatory. 
As has been shown in the case of many inorganic poisons (5)» 
the production of the palmella form is sometimes accompanied in 
these waters by a stimulation of zoospore production. Usually, 
however, the swamp water acts more like low temperatures, producing 
the vegetative response without either accelerating or retarding the 
reproductive activity. 
The palmella response in certain of these waters may 
be due, 
