APPENDIX. BOOK I, 9^3 



Jena, 1874) the structure of the growing-point of the root oi Lycopodium 

 is the same as that described above under Type i. 

 According to Bruchmann the structure of the growing-point of the root of Loetes 



agrees with that described under Type 4. 

 At the growing-point of the root in the Marattiaceae there is a group of several 

 large polygonal cells. From these segments are cut off parallel to the base to 

 form the root-cap, and internally segments are cut off to increase the Plerome. 

 The plerome-segments are further divided by longitudinal walls, and the more 

 external of the cells thus formed constitute the cortex, which is differentiated 

 at a lower level into Dermatogen and Periblem. These roots are thus inter- 

 mediate in their structure between those which have a single apical cell and 

 those which have a small-celled meristem. In the case of stems, those of 

 certain Selaginellx {arborescens, Per'villei, JVallichii, Lyalli) occupy an analogous 

 position. 

 Page 149. For a discussion of the physiological causes of the morphological differ- 

 entiation of Plants, see Sachs, Stoff und Form der Pflanzenorgane, Arb. d. bot. Inst, in 

 Wiirzburg, II. 3, 1880, and 4, 1882: see also Vochting, Ueb. Organbildung im Pflanzen- 

 reich, 1878, and F. Darwin, The Theory of the Growth of Cuttings, Journ. Linn. Soc 

 XVIII, 1881. '' 



Page 153. On the Anatomy and Morphology of the Leaf, see J. Ghatin, De la 

 Feuille, Paris, 1874; and Goebel, Beitr. zur Morphologic und Physiologic des Blattes, 

 Bot. Zeitg. 1880 and 1882. 



Page 163, fig. 122. The root represented here affords a good illustration of the 

 structure of the apex described above under Type 2 ; it is obvious that the original 

 interpretation was the right one, namely, that the root-cap is not developed from the 

 dermatogen. 



Page 166. On the development of the lateral roots, see Janczewski, Recherches sur 

 le Developpement des Radicelles dans les Phanerogames, Ann. d. Sci. Nat, ser. 5, XX, 

 1874. 



In the Equisetacese the plerome- (bundle-) sheath consists of two layers (Van 

 Tieghem), and it is from cells of the inner layer that the lateral roots are developed. 

 Line 5 from the bottom. For ' vascular ' read ' xylem.' 



Page 168, paragraph (e). For another case of the conversion of a root into a stem, 

 see Goebel, Ueb. Wurzelsprosse von Anthurium longifolium, Bot. Zeitg. 1878. 



Page 170. Wel'ujitschia produces two leaves in addition to the cotyledons (see Bower, 

 Q^J. M. S. 1881). 



Page 171. It has been found (see p. 400) that the shoots of Equisetaceae are not 

 endogenous. 



Page 172, paragraph (a). See Heinricher, Ueb. Adventivknospen an der Wedel- 

 spreite einiger Fame, and. Die jiingsten Stadien der Adventivknospen an der Wedel- 

 spreite von Asplenium bulbiferum, Sitzber. d. k. k. Wien. Akad. LXXVIII, 1878, and 

 LXXXIV, i88r. He finds that in Asplenium the adventitious bud is developed from a 

 single superficial cell. 



Page 173, paragraphs (b) and (c). On the adventitious development of organs, see 

 Hansen, Vergl. Unters. ueb. Adventivbildungen bei den Pflanzen, Frankfurt, 1881. 



Paragraph (e). It has been shown by Janczewski and by Famintzin that the lateral 

 buds of Equisetaceae are not of endogenous origin. 



Page 184, paragraph (d). It is pointed out in Book II that the branching of the 

 stem of the Lycopodiaceae is not dichotomous in all cases. 



Page 187. Phyllotaxis. On this subject see Schwendener, Mechanische Theorie 

 der Blattstellungen, Leipzig, 1878. According to him the relative positions of lateral 

 members depends upon (i) the relative size of the lateral members (when they are deve- 

 loped close together), and (2) the increase in length and in thickness of the axis bearing 

 them. 



