COURSE OF BUNDLES IN THE STEM. 



239 



u and v above a and i are bundles entering from the axillary buds of the cotyledons, 

 which apply themselves to the lateral bundles from III and IV. 



To this type belong also Erythrina crista galli, 

 Primus avium, Ribes rubrum, Menispermum dauricum. 



5. Leaves arranged spirally. Leaf-trace of 3 bun- 

 dles, pectinating with the ist and 2nd below. 



Passiflora Vespertilio, Viola elatior, Trapa'olum majus , 

 Cucumis sati-vus. 



6. Leaves spirally arranged. Leaf-trace of 7 

 bundles, all the bundles pectinating with those of the 

 next trace. Saururus cernuus. 



7. Leaves arranged spirally. Leaf-trace of 8 bun- 

 dles, the lateral ones united. Liriodendron tulipi- 



fera, L. 



8. Leaves alternating in t<wo ro'ws. Leaf-trace of 

 3 bundles, pectinating only with the leaf-traces of the 

 same side. Hertia crassifolia, Nag. I.e. 



9. Leaves alternating in two rows. Leaf-trace of 

 3 bundles, which pectinate with the traces of both 

 rows : foliage shoots of Aristolochia Clematitis, A. 

 Gigas, SipLo. (Nageli, /.f.). 



In A. Clematitis (Figs. 96, 97) three bundles enter 

 the stem from the leaf. The median bundle divides 

 immediately into two, which traverse the first inter- 

 node side by side, and, uniting again with one another 

 at the next node, they pursue a common course 

 through the next internode. The two lateral ones 

 pass undivided through two internodes: at the point 

 of exit into the base of the leaf they are united 

 with the two shanks of the median bundle by an 

 anastomosis. Side by side with the two shanks of 

 the median bundle lie, on the right and left-hand, 

 bundles which pass out at the same node, and supply 

 the axillary inflorescence : they are therefore axillary 

 bundles. The whole trace of the lateral structure of 

 a node thus consists in its own internode of 6, in the 

 next lower internode of 5 bundles. It encloses in 



the former an arc of 215°, in 

 the latter of 205°. 



The median bundle of the 

 trace {a, f, I, q, v) as it 

 reaches the four bundles of 

 the leaf-trace of the second 

 node curves to one side, and 

 unites with the lateral bundle 

 of the next lower trace. The 

 median bundles of a row of 

 leaves curve alternately to 

 both sides, e.g. those of the 

 traces i, 5, 9 to the right, 

 those of 3,7, II to the left. At the point of curvature a second shank is formed later, 

 which affixes itself to the other lateral bundle. 



The lateral bundles of the leaf-trace {bc,gh, mn, rs, xy) pursue an individual course 

 through their own internode, they then pectinate with the corresponding ones of the next 



a 



i h d a 



e q c 



Fig. 96. 



/ Jt 



Figs. 96, 97. — Aristolochia Clematitis, after N geli. Fig-. 96. Scheme of the course of 

 the bundles in the stem; the cylindrical surface reduced to one plane, and seen from 

 within. — Fig 97 (20). Transverse section through an internode, at the height of the lower 

 end of Fig. 96 ; further explanation in the text. 



