5 i6 BOTANICAL GAZETTE [june 



pair of scale bundles. At the base of the ovule there are then but 

 two bundles, with xylem and phloem in normal position, and not 

 showing the inverse orientation claimed for T. baccata by Van 

 Tieghem. Miss Aase's figures of T. baccata also show normal 

 orientation at this level. These two bundles become more widely 

 separated and enter the integument at opposite sides (figs. 43, 52), 

 whence they traverse the integument almost to the tip of the ovule, 

 their position being indicated externally by the ridges on the integu- 

 ment. As Miss Aase pointed out, one of the four bundles may 

 terminate before reaching the base of the ovule (figs. 53-56), in 

 which case the odd bundle may behave in the same way as the 

 fused bundle. Ovules with three or four vascular bundles in the 

 integument occur with some frequency, such situations occurring 

 as a result of the failure of the fusion of one or both bundles, 

 in which case each bundle is continued into the integument 

 (figs. 53-60). Frequently when one of the four bundles of the 

 normal cylinder is absent (figs. 54, 55) a 3-ridged integument 

 results, no fusion taking place, but each bundle remaining distinct 

 (figs. 53-60). 



At the level of fusion the bundles are oval (fig. 51), and the 

 fusion bundle remains this shape for some distance into the chalaza 

 of the ovule. At a higher level they begin to widen laterally 

 (figs. 57, 58), whether fusion has taken place or not, until near the 

 upper level of the chalaza they reach their greatest width, both 

 radially and tangentially. They then suddenly become narrow, 

 and pass into the hard integument as narrow strands (figs. 43, 60). 

 The bundles are endarch throughout their course, and at the base 

 of the aril are collateral. Higher up, however, scattered xylem 

 elements, consisting of short spiral-marked tracheids with bordered 

 pits, appear outside the phloem (figs. 57, 58), and in the upper 

 portions of the aril base the bundles consist of the phloem strand 

 surrounded on all sides by the loosely distributed short tracheids 

 (fig. 59) . The tracheids occur only in the aril portion of the chalaza, 

 the bundles as they pass into the integument consisting only of 

 few thin-walled elements of phloem tissue. 



It would seem that the vascular supply to the ovule favors the 

 interpretation of it as terminal and cauline in nature. The vascular 



