37^ 



PRIMA RF ARRANGEMENT OF TISSUES. 



bundle ends in one group of epithema, or two or more converge, so as to end in a 

 common group. The former, for example, is the case in the large leaf-teeth of 

 Fuchsia, Primula sinensis (Figs. 177, 178), and Cucurbita, where the bundle-end is 

 a thick, short strand, derived from the union of several convergent bundles inside 

 the edge of the leaf; also beneath the furrows of the surfaces of the leaf of species of 

 Crassula, in the glandular spots of the surfaces of the leaf of species of Malpighia, &c. 

 The latter is the case in many teeth and crenations of the leaf, especially the broader 

 ones, e.g. Brassica', Papaver, Tropaeolum (Fig. 179), and many others. The arrange- 

 ment of the parts is here such that one bundle coming from the middle of the leaf, 

 and one or more marginal ones on each side, converge towards the epithema, and 

 end at its circumference. Both cases, namely common and special epithemata, often 

 occur side by side, e. g. in leaves of Crassula, in the marginal furrows of the leaf of 

 Saxifraga Aizoon, elatior, and their allies (comp. Unger, /.c.) 



Fir. 179.— Tropaeoluni majus (^o). Course of the ends of the vascular bundles in a piece of tlie edge of the leaf at its median 

 indentation. At e epithema, above which lie the water-pores figured at p. 52, fig. 19. 



In the furrows or spots (mentioned in Sect. 8) of the surface of the leaf of certain 

 species of Ficus, which have incorrectly been supposed to be without vascular bundle- 

 terminations, in the glandular ends of the petiolar appendages of Passiflorae, Mal- 

 pighiaceae (e. g. Stigmaphyllum), and AmygdaleK, and in the glandular prominences 

 or depressions of Acacias, divergent rows of tracheae with short articulations run 

 into an epithema lying below the epidermis. These rows may belong, according to 

 the particular case, to one or more bundles, or in several cases may equally well be 

 considered as one bundle or as several. 



In the furrows of the leaves of Ficus, according to investigations on F. neriifolia and 

 diversifolia, a disc-shaped group of epithema lies below the epidermis, either over a knot 

 of the network of vascular bundles, or over a single bundle ; in the former case the vascular 

 bundles meeting in the knot, break up, as it were, towards the side of the furrow, into 

 numerous short rows of tracheides directed towards the latter; in the second case a 

 bunch of tracheides branches off from the bundle and enters the epithema. 



' Compare Unger, /.c. (above, p. 327), Taf. 2, fig. 17. 



