GERMINATION AND EMBRYOGENY OF GNETUM GNEMON. 285 



Such embryos were figured by Griffith (* Linn. Trans./ 

 vol. xxii). 



27^6 Vascular St/stem of the Seedling. 



From each of the cotyledons five vascular bundles enter 

 the stem^ (fig. 23) ; these curve downwards, and for a short 

 distance pursue an individual course. Soon the marginal 

 bundles of the two leaf systems fuse (fig. 2S d, bundles 

 marked x ), the whole number of bundles being thus reduced 

 to eight. Further down the hypocotyledonary stem small 

 branch bundles are formed, which run parallel to the larger 

 bundles, while the latter oceasionally fuse laterally. Thus 

 the number of bundles found in transverse sections of the 

 lower part of the hypocotyledonary stem is not constant. 

 The arrangement of the bundles in a ring is maintained 

 down the hypocotyledonary stem till the level of the feeder 

 is reached. Here those bundles which are on that side of 

 the stem on which the organ is curve outwards from the 

 ring and pass into the feeder, leaving some three or more 

 bundles behind in the stem; these pursue a direct course 

 downwards into the root (figs. 24, 25). The bundles which 

 enter the feeder branch repeatedly, but run with an almost 

 direct course along the upper side of the organ ; close to its 

 apex they curve sharply, and returning along its under side 

 re-enter the axis of the seedling. A transverse section of 

 the feeder shows a ring of bundles (fig. 26), in which it is 

 often difficult to distinguish the outgoing from the returning 

 system. This is due partly to the branching of the bundles, 

 partly to the formation of lignified elements between them, 

 through the activity of a feeble interfascicular cambium, 

 which appears at a comparatively late stage, and completes 

 the vascular ring. 



It was above stated that three or more bundles pass 

 directly from the hypocotyledonary stem to the root. Some 

 three more return from the feeder and rejoin these ; the six 

 or more bundles then pass downwards together into the 

 root. Of these bundles, two appear stronger than the rest 

 (fig. 24), and the xylem of these may be traced down- 

 wards, and, after rotation, so that the protoxylem takes a 

 peripheral position, they are seen to be continuous with the 

 two primary xylem masses of the root. The phloem of 

 each of these bundles divides into two parts, which unite to 



' Strasburger (' Conif. und Gnet./ p. 115) has observed a similar number 

 as supplying the foliage leaves of an unnamed species of Gnetum ; the 

 number varies, however, in different species. I have also observed seven 

 bundles passing from each of the older leaves of G. gmmon into the stem. 



