628 BOWMAN— ECOLOGY AND 



fresh or salt water. The transpiration as affected by the climate 

 was not of paramount interest, as that has received much attention 

 by such investigators in warm climates as Haberlandt/*'*^ Holter- 

 mann/**^ Giltay,"- Wiesner,^''^ Unger/°* StahP°^ and many others. 

 As mentioned before, the Rhizophora trees grow along the shores 

 of bays and the mouths of rivers, where the above conditions are 

 found, so an attempt was made to study the effect of this environ- 

 ment as evidenced by the transpiration rates of plants in similar, 

 but controlled conditions. At the same time various soils w-ere ex- 

 perimented with. 



Seedlings of the first or second year's growth were secured at 

 Cayo Agua, one of the lower Florida keys, and brought to the Tor- 

 tugas Laboratory on the laboratory yacht, a distance of about ninety 

 miles. The seedlings were found in natural beds under the parent 

 trees along the shores of this island. During the transit some of 

 the seedlings died, but enough were saved to start several hundred 

 cultures. These cultures were made in large heavy glass beakers 

 about ten inches in diameter. 



These seedlings were placed in a jar, in soil and mud, etc., ac- 

 cording to the kind of culture, and the jars filled up with water. 

 The water was of a definitely known concentration of sea water or 

 pure rain water from the laboratory cisterns. The soils ordinarily 

 used were either the native Tortugas sand, a very coarse calcareous 

 sand composed of the remains of calcareous algse, corals, echino- 

 derms, gastropods, etc., or a reddish soil brought down to the labora- 

 tory from the vicinity of Maplewood, N. J. This latter soil ap- 

 peared to be composed of a disintegrated, ferruginous sandstone. 



lo** Haberlandt, G., " Ueber die Groesse der Transpiration im feuchtem 

 Tropenklima," Ebenda. Bd. XXXI., 1898. 



I'^i Holtermann, K., " Die Transpiration der Pflanzen in d"en Tropen," 

 Sitzb. der kgl. preuss. akad. des Wisscn. Berlin, Bd. XXX., 1902. 



^°2 Gilt'ay, E., " Die Transpiration in den Tropen und in Mitteleuropa," 

 II., Ebenda, Bd. XXXII., 1898. 



103 \Yiesner, J., and Pacher, J., "Ueber die Transpiration entlaubter 

 Zweige," Oesterr. Botan. Zcitschr., Wien, Bd. XXV., 1875, p. 145. 



104 Unger, F., " Neue Untersuchungen ueber die Transpiration der Pflan- 

 zen," Ebenda, Bd. XLIV., 1862. 



^'•^ Stahl, E., " Einige Versuche uel)er Transpiration und Assimilation," 

 Botan. Zeitung, Bd. LIL, 1894, p. 117. 



