748 NOTES 



with a more satisfactory apparatus. He finds that, in Vicia Faha, Phaseolus multi- 

 floras and Lupin us albus, both apex and growing zone are geotropically sensitive, 

 the former being by far the more sensitive of the two, and the curvature of the 

 growing zone being without a doubt largely induced by secondary stimuli trans- 

 mitted from the apical region. Ch. Darwin's views were therefore in the main 

 correct. Cf. G. Haberlandt : P.J. 45, 1908, and the literature there cited. 



304. Gaulhofer : Sitzb. Wien, 1907. 



305. Tischler : Flora, 94, 1905. 



306. G. Haberlandt : P.J. 38, 1903. Schroder : Beih. Pot. Centr. 16, 1903. 



307. From unpublished experiments carried out in the Graz Botanical Institute. 



308. Samuels : Ost. Bot. Zeitschr. 55, 1905. 



309. Nemec : Beih. Bot, Centr. 17, 1904. Id. Flora, 96, 1906. 



310. Giesenhagen : Ber. 19, 1901. Schroder : I.e. [306]. 



311. G. Haberlandt : Sitzb. Wien, 115, 1906. 



312. G. Haberlandt : P.J. 38 (1903) and 42 (1905). Id. Ber. 26 (1908). 

 F. Darwin : Proc. Roy. Soc. 71 B, 1903. Bach : P.J. 44, 1907. 



313. Buder : Ber. 26, 1908 (Festschr.). 



314. F. Darwin and Miss Pertz : Proc. Roy. Soc. 73 B, 1904. 



315. Jost (B.Z. 1904, p. 279) exposed roots of Ervum Lens and cotyledonary 

 sheaths of Panicum, for 2 or 3 hours, to centrifugal force of 02 to 05 g. intensity ; 

 pronounced curvatures resulted, although the falling starch-grains remained evenly 

 distributed. This result in no wise conflicts with the statolith-theory ; for when 

 the starch-grains are evenly distributed, it is obviously only the grams adhering 

 to the outer walls (i.e. the walls next the periphery of the revolving body to which 

 the experimental plants are attached) that will exert pressure against the ectoplast 

 under the influence of the centrifugal force. All the curvatures observed by Jost 

 agree with this interpretation. 



316. Ch. Darwin : I.e. [278], pp. 383 sqq. Rothert : Cohn's Beitr. 7, 1896. 



317. F. Kohl : Die Mechanik d. Reizkiiimmimgen, Marburg, 1894. 



318. G. Haberlandt : Ber. 22, 1904. Id. Die Licktsinnesorgane d. Laubbliitter, 

 Leipzig, 1905. Id. Sitzb. Wien, 117, 1908. Von Guttenberg : Ber. 1905. Sperlich : 

 Sitzb. Wien, 116, 1907. Seefried : ibid. Wager : Journ. Linn. Soc. 1909. 



319. Wiesner : Biol. Centr. 19, 1899. 



320. Vochting : B.Z. 1888. 



321. G. Krabbe : P.J. 20, 1889. 





322. It is many years since the author first tentatively suggested that papillose 

 epidermal cells might act as condensing lenses (cf. G. Haberlandt : Die physiol. 

 Leistungen d. Pflanzengewebe, in Schenck's Handbuch, 2, 1882) ; at that time, 

 however, he believed that the sole advantage of this fight- condensation consisted 

 in the increased illumination of the photosynthetic cells. 



