Tli^SUFS OF ANGI0SPEBM8. 



441 



into the second leaf — i.e., the leaf at the summit of the in- 

 ternode under consideration ; the huudles 

 I, in, n descend from the leaf next above, 

 and^ and q from the one still higher. 



541. — We may get a clearer idea of the 

 mutual relations of the bundles if we con- 

 ceive the bundle-cylinder to be split down 

 on one side, and spread out upon a plane. 

 In Fiff. 317 we have such a diagrammatic Kg. sie. — CroBs-sec- 



o o tion of the next to the 



representation of the arrangement of the lower intemode of Fig. 



1 11 ■ n / » f-y, 7 ,. 315,showingthearrange- 



bundles m the stem of Stacliys angusti- ment ot the bundles, tiie 



J, T. T-r ii_e TT _L lettering as in Fig. 315. 



folxus. Here each leaf sends down two — Aftei-T>rageii. 



bundles, which pass through two internodes and then unite 



with other descending bundles at 

 their middle points. The fibro- 

 vascular cylinder is thus compos- 

 ed when complete of repeatedly 

 branching bundles. A cross-sec- 

 tion (Fig. 318) through the stem 

 at some distance above the lower 

 leaves in Fig. 317 

 shows that each 

 internode c o n - 

 tains bundles 

 from two pairs of 

 leaves — i.e., those 

 at its summit and 

 those at the sum- 

 mit of the one 

 above. In Fig. 

 318 the pairs of 

 bundles marked c and d descend 

 from the leaves c and d, while 

 those marked e and/ pass down 

 from the leaves one intemode 



Fig. 317.— Diagram showing the ar- higher Up. 

 rangement f)f the fibro-vasciuar bun- t . ., - ,-,-.. 



dies in stadiys angustifoUm. a, 6, in a Similarly Constructed dia- 



— d. G. — f,e, — Q.h^ — 2, A, thcpoints s ^-^ c\ i t 



from which the successive pairs of giam 01 tile UbrO-VaSCUlar Cylin- 

 leavesspring.-AfterNageli. ^g^. ^f jj^,.^-^ ^^^^^ ^j,.g_ g^g^ 



projected upon a series of transverse and vertical lines to 



Fig. 318. — Cross- 

 section of the next 

 to the lower inter- 

 node in Fig. 317, 

 showing the disposi- 

 tion of the bundles, 

 the lettering as in 

 Fig. 317.— After Na- 

 geli. 



