Shaw. — The Seedling Structure of Araucaria Bidwillii. 329 
root. All three fuse, giving rise to a triangular mass of xylem and phloem 
enclosing a pith (Diagram VI, Fig. 6) ; from each angle of this triangle 
a branch is sent out laterally (Diagram VI, Fig. 7). The exact fate of 
these branches was not quite established ; it is believed that they simply 
died out in the parenchyma, although the possibility is not excluded that they 
went to supply secondary roots. At all events, the remainder of the triangular 
mass rounds itself off to form a single concentric oblong stele. In the 
centre of this stele a little diarch xylem plate now appears ; it seems to arise 
by the separation of the protoxylem from the inner surface of the secondary 
xylem of the stele (Diagram VI, Fig. 8). Throughout the whole of the 
seedling enormous resin ducts run longitudinally in the cortex, and at the 
point at which the root becomes diarch frequent anastomoses occur. 
Conclusions. 
The essential points of the above type of seedling structure seem 
to lie in the variation in the number of cotyledonary bundles entering the 
hypocotyl, in the number of protoxylem groups in the root, and in the 
reduction of the structure in the younger portions of the latter. 
