56 THE OPHIOGLOSSALES 



The two bundles, belonging respectively to the leaf and the root of the bud, 

 join the bundle of the primary root very near together, and from near this point of 

 junction the development of the tracheary tissue proceeds toward the apices of the 

 young organs. The first tracheids, like those found in the median region of the 

 young sporophyte, are short reticulate ones. 



The first leaf of the bud grows rapidly and closely resembles the cotyledon in 

 form and size, and at first it often looks as if two young sporophytes of equal size 

 were growing from the prothallium, but a very slight examination shows that the 

 second leaf belongs to the bud upon the primary root. The second leaf of the bud 

 also seems to be formed independently of the stem apex and arises nearly opposite 

 the first one (fig. 37, A^. Its development is practically the same as that of the 

 first leaf, and it pushes through the outer tissue of the root at a point removed by an 

 appreciable distance from the base of the first leaf, from which it is separated by a 

 sheath about the base of the latter, formed by the outer root tissues. 



The vascular bundle in the second leaf is soon developed and can be followed 

 down to the bundle of the first root of the bud, to which it bears somewhat the same 

 relation that the bundle of the first leaf of the bud does to the primary root of the 

 sporophyte. Fig. 37 will show clearly the arrangement of the vascular bundles in 

 a young bud in which the first leaf is fully developed, while the second and third are 

 pretty well advanced. The latter (/") shows very plainly the conspicuous apical 

 cell and the beginning of the leaf trace. The apical cell of the stem at this time is 

 sufficiently conspicuous, but the amount of tissue surrounding it is quite limited 

 in extent. In fig. 37, D, it is probable that the fourth leaf has begun to develop. 

 Above the apex of the stem the cavity of the leaf sheath can be clearly seen. By 

 this time the first root of the bud has emerged below the first leaf and the tracheary 

 tissue is well developed in its basal region. 



The second root of the bud originates below the apex of the stem in the vicinity 

 of the base of the second leaf. The vascular strand of the third leaf joins it, and the 

 third leaf seems to have somewhat the same relation to the second root that the 

 second leaf does to the primary root. 



The study of the development of the young bud shows that, up to the time of the 

 production of the third leaf, the young organs arise quite independently of each 

 other from the tissue of the primary root. The young sporophyte is, so to speak, 

 made up by the union of several independent members. The third and fourth 

 leaves arise from the stem apex as all of the later ones do, but the first and second 

 leaves and the first root show no recognizable relation to the stem apex. Their 

 vascular bundles are directly connected with the bundle of the primary root of the 

 young sporophyte, and are in no way associated with the tissues which belong to 

 the stem region of the bud. No material was available for the study of the origin 

 of the leafy bud in 0. pendulum, but the first leaf evidently develops very much 

 later than it does in 0. moluccanum. Young leaves 10 centimeters or more in length 

 were found, which, there is some reason to suppose, were the primary leaves of the 

 young plant; but they were not recognized as such at the time they were collected 

 and it is therefore impossible to say whether they really were the first leaves devel- 

 oped. After the study had been made of the young sporophyte in O. moluccanum, 

 and the secondary origin of the stem apex was made out, it was recognized that these 

 small leaves in 0. pendulum also were probably the primary leaves of the plant, but 

 it was too late then to trace the connection of the roots from which they developed 

 to their connection with the primary root of the young sporophyte. 



I was unable to determine just how soon the fertile leaves are developed from 

 the young sporophyte in 0. moluccanum. In all of the specimens that were sectioned, 



