58 THE OPHIOGLOSSALES 



leaf and all of these leaves were sterile, nor could any indication of the develop- 

 ment of a central spike be seen in the development of the fourth leaf. The first 

 leaf of the bud, like the cotyledon, showed two large lacunae in the petiole, but in 

 the second leaf there was but a single one and this was interrupted at intervals, 

 while the petiole of the third leaf appeared almost solid, there being only small, 

 irregular, intercellular spaces, such as are always found in any loose parenchyma. 

 All of the vascular bundles are collateral. In the lower portion of the third leaf 

 eleven tracheids could be seen in the transverse section of the bundle, but higher 

 up the amount of tracheary tissue was reduced. 



Figs. 38, A, and 39, A, were cut just above the stem apex and showed clearly 

 the arrangement of the first four leaves. The youngest leaf is still entirely surrounded 

 by the conical stipular sheath belonging to the third leaf. Fig. 2>^,A, is taken imme- 

 diately above the stem apex and passes through the very young fifth leaf. This 

 section shows very satisfactorily the arrangement of the first five leaves. Section C 

 lies a short distance below the stem apex, r is the root from which the bud has 

 arisen, and the group of tracheids at its junction with the bud marks the point 

 of union of the bundles of the first leaf and the first root of the bud. In the center 

 of the section may be seen a mass of large-celled parenchyma, the central pith of the 

 stem, which is derived from the large-celled meristem of the stem apex. The broken 

 ring of procambium surrounding the pith is composed of obliquely cut traces of the 

 fourth and fifth leaves and the basal tissue of the second root of the bud. The leaf 

 traces from the second and third leaves are still free in the cortical tissue of the young 

 stem. E and F pass through the base of the bud. The stout bundle of the first 

 root is seen connected with the bundle of the root upon which the bud was developed, 

 and the second leaf trace (/^) bends in to meet the bundle of the root but is cut 

 at a level above the point of junction. Close to the second leaf trace is the lower 

 part of the fourth leaf trace, which is connected with the trace of the second root 

 of the bud. The steles of both the first and second roots of the bud run horizon- 

 tally across its base before they emerge, and the leaf traces are almost perpendic- 

 ular to these. The second leaf trace at the base of the bud joins the stele of the 

 first root and the short tracheids curve out trom the opposite side of the bundle of 

 the first root to unite with the base of the third leaf trace, which does not, as might 

 have been expected, show any very obvious relation to the second root. At the 

 point where the first root bends downward to emerge from the overlying cortical 

 tissue the tracheary tissue of this, with the bases of the leat traces, forms a large 

 mass of irregular, broad, reticulate tracheids, occupying the center of the base of 

 the young bud. It was probably the presence of this mass 01 tracheary tissue at the 

 base of the bud which led Rostowzew to state that the bundle of the bud is at first 

 solid. It is possible that the buds formed on the old roots ot 0. vulgatum may be 

 somewhat different in structure from the early buds in 0. moluccanum and that 

 there really may be such a solid stele at its base. 



According to Rostowzew (Rostowzew 1, 2) and Poirault (Poirault 2), the buds 

 upon the older roots of 0. vulgatum usually arise close to the apex, much as they 

 sometimes do in the formation of the bud upon the primary root of O. moluccanum. 

 Van Tieghem thought that the apex of the root itself became changed into the 

 leafy shoot, but both Poirault and Rostowzew demonstrated that the young bud 

 originated from a segment of the apical cell of the root and not from the apical 

 cell itself; the latter continues its growth and the root thus grows beyond the 

 point of insertion of the young bud. Rostowzew states that an outer cell of the 

 segment divides into two superimposed layers, of which the superior one, or the 

 one nearest the root apex, gives rise to the stem apex of the bud, while from the lower 



