126 



BOTANY 



PART 1 



(Fig. 136). The numerous bundles entering the stem from axillary 

 shoots pursue a similarly curved course to those entering from leaves. 



In addition to the leaf- 

 trace bundles or COMMON 

 BUNDLES, which are common 

 to both leaf and stem, there 

 are others, called CAULINE 

 BUNDLES, which belong solely 

 to the stem, and again others, 



FOLIAR BUNDLES, which, Oil 



entering the stern from the 

 leaf, at once coalesce with 

 other bundles and have no 

 independent existence in the 

 stem. The bundles of the 

 Pteridophytes are continued 

 as cauline bundles in the stem, 



Fio. 135. Cieiiuitis viticella. End of a branch which 

 has been made transparent by the removal of the 

 superficial tissues and treatment with caustic 

 potash. The emerging strands have been slightly 

 displaced by gentle pressure. The two uppermost 

 pairs of young leaves (bli, W 2 ) are still without 

 leaf-traces, r, Apical cone. (After NACF.LI.) 



and those from the leaves join on to the 

 bundles of the stem. 



3/tl 



nn 



FIG. 136. Diagram showing the 

 course of the vascular bundles 

 of Monocotyledons of the Palm 

 type, with alti-rriatiiix, two- 

 ranked amplexicaul leaves. The 

 numbers indicate the sequence 

 of the leaves ; m, median bundle. 

 (After DE BARY.) 



The stems of many Dicotyledons (Begonia, 

 Aralia) possess cauline bundles in addition to leaf- 

 traces. The cauline bundles are situated in the 



pith within the ring of leaf-trace bundles in the internode, and at the nodes are 

 connected by branches with the leaf-trace bundles. 



