NOTES 7 25 



Vaupel : Flora, 92, 1903. Paul : Engler's Jahrb. 32, 1903. In the last-cited paper, 



various facts and arguments are adduced in support of the view that the rhizoids of 

 Mosses are always primarily organs of attachment, and have little to do with absorp- 

 tion. This view is no doubt correct, so far as epiphytic and aquatic species are con- 

 cerned ; but all Mosses that grow rooted in the ground, or rather all those that ha \ e 

 a central water-conducting strand in their stems must certainly absorb water 

 through their rhizoids in the same way as a Higher Plant does through its root- 

 system. 



Fern-prothalli and Liverworts occasionally bear multicellular rhizoids ; these 

 have been recorded, for example, in Danaea (Brebner : A.B. 10, p. 120) and in 

 Gottschea (Goebel : Flora, 96, 1906, pp. 103 sqq.). In the latter case it is particularly 

 the expanded and lobed ends of the rhizoids that are septate ; whether this point is 

 of any physiological importance, is not known. 



122. Velamen. Unger : Sitzb. Wien, 13, 1854. Id. Anatomie u. Physiologic d. 

 Pflanzen, 1855, pp. 306 sqq. Duchartre : Journ. soc. imp. et centr. 1856, p. 67. 

 Oudemans : Abh. Akad. Amst. 1861. Chatin : Mem. soc. Cherb. 1856, p. 7. Leitgeb : 

 Denkschr. Wien, 24, 1864, pp. 179 sqq. Id. ISitzb. Wien, 49, 1864 (two papers). 

 A. F. W. Schimper : Die epiphytische Vegetation Amerika's, Jena, 1888, pp. 46 sqq. 

 Goebel : Prlanzenbiologische Schilderungen, 1, Marburg, 1889, pp. 188 sqq. Meinecke: 

 Flora, 78, 1894, pp. 133 sqq. Nabokich : Bot. Centr. 80, 1899. 



With reference to the exodermis, cf. also Von Hohnel : Sitzb. Wien, 76, 1877, 

 and Kroemer : Bibl. Bot. No. 59, 1903. 



123. Von Mohl : Vermischte Schriften, pp. 294 sqq. Oltmanns : Ub. d. Wasser- 

 bewegung in d. Moospflanze (Inaug. -Dissert), 1884. Russow : Schriften d. Naturf.- 

 Ges. zu Dorpat, 3, 1887. Lorch : Flora, 1894, pp. 424 sqq. 



124. For the earlier literature dealing with absorption of water by foliage- 

 leaves, the reader is referred to the compilations of Osterwald (Wiss. Beilage z. 

 Programm d. stadt. Gymnasiums in Berlin, Easter, 1866) and Burgerstein (27ter 

 Jahresber. d. Leopoldstadter Commimalgymnasiums in Wien, 1891). Further 

 note Lundstrom : Prlanzenbiologische Studien, 1, and Wille : Cohn's Beitr. 4, 

 1887 (adaptations in relation to rain and dew). Wiesner : Sitzb. Wien, 86, 1883. 

 A. F. W. Schimper : I.e. [122], pp. 66 sqq. Id. Bot. Centr. 17, 1884. Volkens : 

 Die Flora d. agyptisch-arabischen Wiiste, Berlin, 1887, pp. 31 sqq. Emily Gregory : 

 Comp. Anat. of the felt-like hair-covering of leaf-organs, Zurich, 1886. Mez : P.J. 

 40, 1904, and Steinbrinck : Flora, 94, 1905 (Bromehaceae). 



125. According to Mez, the thick outer walls of the head also have an important 

 part to play in the absorption of water by the scale-hairs. When wetted , these walls 

 swell and curve outwards. As a result, the cavities of the head-cells which are 

 almost entirely obliterated in the dry state regain their proper dimensions ; being 

 vacuous, they exert a powerful suction, and are thus able to draw in any water that 

 lodges on the outside of the swelling hair. Steinbrinck raises various objections 

 to this theory, and maintains that the action of the absorbing hairs of Bromeliaceae 

 is entirely dependent upon the cohesive power of water. (For a discussion of cohesion- 

 mechanisms see below, Ch. XL). 



126. Treub : Natur. Verb. Acad. Amst. 19, 1879 (Orchidaceae). Id. Ann. Buit. 

 3, pp. 79 sqq. Warming : Engler's Jahrb. 4, 1883, pp. 517 sqq. G. Haberlandt : 

 Ami. Buit. 12, 1893, pp. 91 sqq. (mangroves). Koorders : Engler's Jahrb. 21 (Tectona). 

 Balicka-Iwanowska : Flora, 1899 (various Gamopetalae). Goldflus : Journ. de 

 bot. 12 (1898) and 13 (1899) (Compositae). Lloyd : Mem. Torrey Bot. Club, 8, 



