CONNECTION OF THE BUNDLE-SYSTEMS. 309 



necting bundles, one in Quercus, in Taxus about three, which run down from the 

 upper margin of the gap of the leaf-bearing shoot to the bundles of insertion. By 

 means of these and further ' completing bundles ' the point of connection of the pith 

 of the main and axillary shoots is soon enclosed by a ring. The completing bundles 

 doubtless belong to the secondary formations of intercalary bundles (Chap. XIV) ; 

 the same is probable for the above connecting bundles, but their relation to the leaf- 

 traces of the axillary shoot requires more exact investigation. 



As regards the insertion of the bundles of axillary shoots, two or more of which are 

 seated one above another, Frank's statements may here be reproduced word for word 

 {I.e. p. 388), but the subject is recommended for further research. ' In Rubus two buds 

 are seated in the axil of the leaf closely one above another,"their vascular bundle-systems 

 are united in the lower parts one with another, and are connected with the vascular 

 system of the stem as though they belonged to one single axillary bud. After both 

 lateral series (i. e. the branches of the two original bundles of insertion, De Bary) have 

 united at their anterior ends (i. e. next the leaf which bears the shoot) each separates at 

 the middle, and the anterior halves close up to form a circular system for the lower bud. 

 The remaining posterior halves soon unite at their anterior ends and form the vascular 

 bundle-system of the upper bud. The posterior parts of both circles of vascular bundles 

 are here also closed by descending bundles, which accordingly arise in the case of the 

 lower bud from the vascular bundles of the upper. — In the axillary buds of Lonicera 

 Xylosteum, of which often as many as four are seated one above another, but which are 

 usually separated some distance one from another, and the uppermost of which can hardly 

 be distinguished externally from an adventitious bud, the lower parts of the vascular 

 bundle-systems are also inserted between the members of the vascular bundle-ring of the 

 stem, but in this case each system is independently connected with the stem, since the 

 gap of the vascular bundle-ring of the mother shoot closes above each bud, and only 

 opens again immediately below the insertion of the next, at which point the bundles of 

 the bud arise on both sides from the margins of the open vascular bundle-ring.' 



The third, less common case of insertion of the axillary bundles outside the 

 closed bundle-ring of the leading shoot occurs in the Umbelliferse, though not in all 

 of them. The bundles of the leaf-trace of the lowest internode of the axillary shoot 

 unite ill this case at the node of the leaf which bears the shoot, to form one cortical 

 bundle, which immediately divides into two arms ; these pass off right and left, and 

 embrace the bundle-ring of the leading shoot transversely like a girdle. From this 

 girdle branches arise in pairs side by side and pass downwards. Each of these pairs 

 bestrides one bundle of the trace of the leaf, which bears it, from above and outside, 

 and inserts itself on its two sides, at the point where it curves outwards from the 

 bundle-rings of the leading shoot. The bundle-system of the axillary shoot is thus 

 attached outside the ring of the stem ty the pairs which bestride the same number 

 of emerging bundles of the leaf which bears it. It thus embraces either the whole 

 circumference of the node, bestriding all the emerging bundles of the stem-embracing 

 trace of the leaf which bears it — Foeniculum, species of Heracleum, Chaerophyllum, 

 Myrrhis, and Archangelica ; or a part of it bestriding only some few bundles of the 

 leaf which bears it — ^Ethusa Cynapium. A continuity of pith between the shoots of 

 both orders is thus only possible by the narrow medullary rays. 



The phenomenon stands thus in the mature plant ^ The exact study of the 



' If I am not mistaken, it has been long ago described by C. F. Schimper as ' Astkorb ; ' I have 

 not succeeded in my attempts to find the reference. 



