oo Mite temperatures, and noted that the rheotropic ; 
178 BOTANICAL GAZETTE 
used, if any. Jénsson suspended his seedlings with their roots. 
immersed in water conducted from a hydrant through a trough. 
In 1896, 1 read before the American Association for 
Advancement of Science a preliminary account of ext 
experiments on the rheotropism of roots of seedlings. 
abstract of this paper was published the same year in the 
BoTANIcAL GAZETTE,’ as well as in the Proceedings of the American 
Association for the Advancement of Science, and was 
reviewed in the Botanischer Jahresbericht; yet it seems wholly 
have escaped theattention of the twoauthors soon to be mentiones 
In the preliminary account just cited, seventeen species of Y 3 
were reported, eight of them showing positive rheotropism, and 
nine showing no response to the streaming of the water. Tt 
shown that definite relations exist between velocity of flow af 
response, that the latent period is influenced by various ! 
of the environment, that many roots are not responsive 
stream of water, that all roots which did respond were [| 
that there are various degrees of sensitiveness 10 
‘Species. Some attention was given to the nature of the 
and it was suggested that it might be found to be pressur 
Very recently two authors have published papers 0? - 
ject of rheotropism. Berg® used the same @ p 
Jénsson employed, and another consisting of a basin . 
_ which he revolved seedlings fastened to a disk. By ba 
he found the roots of eleven plants to be positi Hy: 
while the root of Glycine hispida gave no responses 
three roots of the last species grew suitably © for 
devised a still better apparatus for securing strea® 
this consisted of a basin, to the water in which was 
motion by a jet of water discharged in the basi 
direction. Berg found the latent period of several 
% the third or fourth millimeter zone from the ap 
a Newcomer : Rheotropism and the relation of response to: 
+ 242. 1896; Proc, Amer. Ass. Adv. Sci. 1896 ; Bot. J 
®Berc: . Studien iibe seh. ‘of tom Keimwurz 
_ Universit. ae. 52: = 4 a 
