ENDS AND CONNECTIONS OF THE BUNDLES. 



379 



normal. Towards the'end they are tapered, and the xylem and phloem diminish in such 

 a manner, that here also the ultimate termination consists only of one or a few rows 

 of short tracheides. They are distinguished by the fact that within the lamina of the 

 leaf, as if to replace the finer branches, the edge of the xylem is expanded throughout 

 its entire length into a border, consisting of rows of short tracheides inserted in the 

 parenchyma of the leaf. This fringe of tracheides, which was first accurately described 

 by Frank in the case of Taxus', and afterwards more generally demonstrated by MohP, 

 is absent, or at least extremely feeble, in Larix europaea alone of forms known to me : 

 it arises, in the case of the Abietinese, exclusively from the outer, remote edges of 

 the pair of bundles, in the other cases investigated from both sides of each of them. 



Fi^'. i8i. I'ig. 182. 



FtGS. 181, 182.— Rochea coccinea (200). Fig. 181. Fragment of tlie epidermis from the edge of the leaf. 5 water stoma ; 

 s air stoma, with subsidiary cells. The scattered dots are wart-shaped projections of the outer walls. — Fig. 182. Section through 

 . the edge of the leaf vertical to the surface, e — g epidermis, .S" water stoma, n subsidiary cell, ^ somewhat thick vascular bundle 

 in cross-section. The meshes with thicker and double outlines are the sections of bundles of trachea- which run to neighbouring 

 bundles ; the more delicate outlines are those of the accompanying elements. A short strand goes off from d and runs towards -S"; 

 the tracheides of which it consists diverge and embrace the delicate-celled .group of epithema lying between 0,^, and .S. All 

 round is large-celled chlorophyll-parenchyma. 



It is attached to the xylem by means of one or two longitudinal rows of tracheides, 

 more or less frequently interrupted by parenchymatous cells, and from here projects 

 on each side into the surrounding parenchyma ; in most of the species it has the 

 form of a plate, which is either plane or a little curved, and approximately follows 

 the direction of the leaf-surfaces (Taxus, Cephalotaxus, Torreya, Taxodium semper- 

 virens, Cunninghamia (Fig. 183), Juniperus (Fig. 184), Thuja, Thujopsis, Gingko), 

 or is curved from each side round the body of the vascular bundle, and is separated 

 from the latter and from the plate on the other side only by a few rows of parenchymatous 



1 Botan. Zeitg. 1864, p. 167, Taf. IV. 



^ Ibid. 1871, p. 10. Mohl calls the tracheide-border Transfusion-tissue. [See also Zimmer- 



mann, iiber das Transfusions-Gewebe, Flora, 1880, p. 2,] 



