XI] 



WATER-GLANDS 



205 



Fig. 1 95. Part of an adult leaf of Pleridium aqiii- 

 linum (L.) Kuhn, natural size. « = nectary, in 

 form of a small often coloured swelling. (After 

 Potonie.) 



Fig. 196. Pinna of Polypodiuni vulgar c, L. , seen from 

 below, natural size, showing the water-glands at the 

 ends of the veins. i>' = a water-gland enlarged about 

 80. (After Potonie.) Both from Engler and Prantl. 



fidence that simple hairs are a primitive featiwe, and that branched hairs and 

 in partictdar flattened scales are an indication of advance from that simple 

 state. Evidence of this advance parallel with other indications of advance 

 in other characters may be found in various phyletic sequences, and fully 

 substantiates the correctness of the conclusion thus stated. 



BIBLIOGRAPHY FOR CHAPTER XI 



186. De Bary. Comparative Anatomy. Engl. Edn. Oxford. 1884. Hairs, pp. 54, 88. 

 Sclerenchyma, Chap, x, p. 417. 



187. Prantl. Schizaeaceen. Leipzig. 1881, p. 37. 



188. Kuhn. Die Gruppe der Chaetopterides. Berlin. 1882. 



189. Renault. Botryopteris forensis. Flore Foss. d'Autun et d'Epinac. Part ll, p. 33. 



190. Christ. Elaphoglossum. Denkschr. d, Schweiz. Naturforsch. Ges. xxxvi, Zurich, 

 1899. 



191. Seward. Matonia. Phil. Trans. 1899. Dipteris. Phil. Trans. 1901. 



192. Engler & Prantl. Natiirl. Pflanzenfam. i, 4, p. 59. 1902. 



193. Bower. Studies in the Phylogeny of the Filicales, passim. On pneumatophores. 

 Studies. I. Plagiogyria. Ann. of Bot. 1910, p. 427. 



194. Campbell. Eusporangiatae. 191 1, p. 150, Fig. 126. 



195. Haberlandt. Physiological Plant-Anatomy. Engl. Edn. 191 4. Chap. IX, p. 423. 



