692 
Hill and de Fraine. — On the 
endarch position. Very soon the phloem-ring becomes thinner and breaks 
at the two points opposite the protoxylems of the seed-leaf-traces ; but, 
before this rupture is actually accomplished, each xylem-mass derived from 
a cotyledon bifurcates, and the protoxylem undergoes a certain amount of 
rotation, which, however, is not very pronounced and is unequal in degree 
in different instances ; in fact the movement results in nothing much 
further than the concentration of the protoxylem units in the plane of the 
cotyledons. 
The completion of the division of the vascular tissues results in the 
exposure of the protoxylems, and in the formation of two well-defined 
masses of phloem. Concurrently, the metaxylems of the seed-leaf-traces 
fuse with the adjacent wood of the plumular strands ; thus the essential 
features of a root-structure obtain (Diag. 1, Fig. 3). It is to be noted that, 
at this region, the protoxylem elements are still arranged rather tan- 
gentially, but they gradually become aggregated more closely together, 
forming with the metaxylem a well-defined diarch plate, and separated 
from the endodermis by a starch-containing parenchymatous tissue about 
seven cells in thickness (Diag. 1, Figs. 4 and 5). 
C. Fortunei and C. drupacea. The available material of these two species 
was too scanty to trace the sequence of the transition changes in any 
detail ; sufficient, however, was made out to warrant the assumption that 
they differ in no important feature from the foregoing species. 
The older roots show a well-marked assise de scnrfien , a character which 
has already been described in this, and also in Taxns and Torreya by 
Van Tieghem. 1 
Taxns baccata , Linn. The seedling in its external features resembles 
Cephalotaxus and Podocarpns (Figs. 3, 3^, 3#, Plate XXXV) ; and, further, 
the structure and transition-phenomena resemble those of Cephalotaxus , and 
have already been described by Strasburger, 2 so that it is only necessary 
to draw attention to a few minor characters. 
The single bundle of each cotyledon exhibits a mesarch structure, but 
the number of centripetal elements are very few indeed (Fig. 6, Plate XXXV). 
The rearrangement of the vascular tissues begins at the level of the 
cotyledonary node by the xylem taking on a V-like arrangement with the 
protoxylem occupying the apex which is directed outwards ; this is quickly 
followed by the division of the phloem into two parts. During the inward 
journey these changes become more marked, and, as the metaxylem travels 
inwards more quickly than the protoxylem, the latter for a time is mesarch 
in position (Diag. 3 , Fig. 4). A continuous vascular ring is not formed as 
in the case of Cephalotaxus . The separate phloem-masses of each coty- 
1 Van Tieghem : Recherches sur la symetrie de structure des plantes vasculaires (Ann. Sci. Nat., 
Bot., xiii, 1870-1). 
2 Strasburger: Die Coniferen und die Gnetaceen (Jena, 1872). 
