NOTES 741 



the principal function of lenticels. Cf. Note 28 in the third [German] edition 

 of this work (p. 427). 



235. Hannig : B.Z. 1898, and the literature there cited. 



236. Leitgeb : Denkschr. Wien, 24, 1864. pp. 2U4 sqq. A. F. W. Schimper : 

 Bot. Centr. 17, 1884, p. 275. Janczewski : Ann. Sci. Nat. 2, 1885. Jos. Muller : 

 Sitzb. Wien, 109, 1900. 



237. Frank : Entstehung d. Intercellularraume, Leipzig, 1867. Id. Beitr. /.. 

 Plianzenphysiologie, Leipzig, 1868. 



238. Strasburger : P.J. 5, pp. 297 sqq. Pfltzer : P.J. 7, pp. 533 sqq. Rauter : 

 Mitth. Steiermk. 2, 1870. G. Haberlandt : Mitth. Steiermk. 1880. 



239. Most of the early anatomists employed the term " gland " somewhat indis- 

 criminately, often identifying structures as glandular organs on very superticial 

 grounds. Link was the first to point out, that no structure ought to be termed a 

 gland unless it is really secretory in function. A fairly precise definition of glands 

 is to be found in Meyen (tjb. d. Secretionsorgane d. Pflanzen, 1837), although that 

 author still includes guard-cells and stinging-hairs under that name. Unger (Anat. 

 u. Phys. d. Pflanzen, 1855) reckons both uni- and multicellular excretory organs 

 among glands. 



Among more recent authors, De Bary proposes to restrict the term gland to 

 dermal secretory organs, and to call internal glands " intercellular secretory reser- 

 voirs " (Comp. Anat. p. 92, pp. 133 sqq.). Evidently De Bary's standpoint is a purely 

 morphological one ; and his suggestion, if carried out, would lead to the artificial 

 separation of structures which are closely related both physiologically and anatomi- 

 cally. As a matter of fact, the term internal gland has been used in its original sense 

 by several authors since De Bary's objection was published (e.g. by Unger [Anat. 

 Unters. lib. einige Sekretionsorgane d. Pflanzen], and Sachs [Lectures]. 



240. Unger : Sitzb. Wien, 28, 1858. De Bary : Comp. Anat. pp. 50 sqq. and 

 375 sqq. Moll : Versl. Akad. Amst., ser. II., 15, 1880. Volkens : Jahr. Bot. Gart. 

 Berlin, 2, 1883. Potonie : Sitzb. Naturf. Berlin, 1892. Gardiner : Proc. Camb. 

 Phil. Soc. 5. G. Haberlandt : Sitzb. Wien, 103, 1894. Id. ibid. 104, 1895. Id. 

 Ber. 12, 1894. Id. P.J. 30, 1897. Id. B.Z. 1898. Nestler : Sitzb. Wien, 105, 1896. 

 Id. ibid. 108, 1899. Id. Ber. 17, 1899. In the first of the above-cited papers, Nestler 

 cast doubt upon the author's interpretation of the clavate hairs of Phaseolus as 

 hydathodes, suggesting tentatively that the exudation of water from the leaves 

 of this plant might take place through the stomata ; in his two later papers, however, 

 Nestler records his entire agreement with the author's views. Spanjer (B.Z. 1898) 

 denies the existence of epidermal hydathodes (trichome-hydathodes), and also 

 attempts to disprove the active role of the protoplasts in various cases. (Cf. G. 

 Haberlandt's remarks in B.Z. 1898, p. 177). Von Minden : Bibl. Bot. No. 46, 1899. 

 Lepeschkin : Flora, 90, 1902. Lepeschkin concludes, on quite insufficient grounds, 

 that hydathodes are superfluous structures, " the existence of which at the present 

 time is largely a matter of hereditary tendency." Areschoug : Bibl. Bot. No. 56, 

 1902. Molisch : Ber. 1903. Krafft : Syst.-anat. Unters. d. Blattstruktur b. d. 

 Menispermaceen (Inaug.-Diss. Erlangen), Stuttgart, 1907. 



24 1. Scherffel : Mitth. Graz. G. Haberlandt : P.J. 30, 1897. Goebel : Flora, 

 1897. Groom : A.B. 11, 1897. 



241a. Hydathodes of Lobeliaceae (p. 495). Tswett : Rev. gen. 19, 1907. 



