BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS 54I 



bundle is continued beyond to the blossom-end of the fruit. 

 There are also five alternating bundles which diverge a little higher 

 up than those in the preceding and each one passes between two 

 carpels, giving off an internal branch to the inner or ventral face 

 of the carpel. The vascular system in the apple is shown diagram- 

 matically in plate 33, figures 9 and 10. Ten primary vascular 

 bundles demark the cortex and pith regions in the apple. Five of 

 these bundles are found directly opposite the carpels and the 

 other five alternate with them. The carpellary vascular system 

 arises from these primary strands. A dorsal strand supplying the 

 exocarp arises from each of the primary bundles opposite a carpel. 

 A ventral strand which eventually branches, producing two strands, 

 arises from the alternating primary bundle. These strands pass 

 through the placentae of the carpels and again branch to supply 

 the ovules. The dorsal and ventral strands eventually anasto- 

 mose in the region of the style. The primary strands branch 

 repeatedly to supply the sepals, petals, and stamens, and the 

 tissue of the cortex. The ten primary bundles finally anastomose 

 in a very small ring at the apex of the greatly enlarged fruit. 

 In the longitudinal section in figure 9 one of the primary vascular 

 bundles is shown with the dorsal bundle of the carpel which arises 

 from it. One of the ventral strands extends along the inner 

 surface of the carpel and sends a branch to the ovule. The anasto- 

 mosing of the dorsal and ventral strands is indicated. The 

 different regions of the fruit may be identified in the drawing as 

 follows (a) representing the unused portion of the axis of the 

 flower; (b) the exocarp of the carpel separated from (c) the pith, 

 by the dorsal vascular bundles; and (d) the cortex, which is dis- 

 tinct from the pith and is outlined by the primary vascular bundles. 

 The same regions are indicated by similar letters in the cross 

 section in figure 10. It will be observed that the five primary 

 vascular bundles opposite the carpels are in a circle of a slightly 

 larger diameter than the circle of the intermediate bundles. The 

 small row of dots demarking the exocarp of the carpel represents 

 the distribution of branches from the large dorsal bundle of the 

 carpel. The two ventral bundles in each carpel are inconspicuous. 

 Within each carpel two ovules are shown. The dorsal primary 

 bundle and the suture formed by the infolded edges of the carpel 

 lie on radii passing through one of the outermost primary vascular 



