406 Scott & Sctrgant . — On the Development of 
lower nodes. Thus a complicated network is formed in which 
no ground plan can be recognized. 
The formation of a vascular girdle at each node is indicated 
even in the youngest seedlings we possess (Fig. i). But the 
bundles which unite these are not completely fused with each 
other, and can be distinguished throughout their course. The 
tendency to anastomose is also shown very early. We have 
found an irregular lateral anastomosis in a seedling no older 
than that drawn in Fig. 4. No great complications have yet 
arisen from this cause however, and therefore the course of 
the leaf-traces can be clearly followed from their entrance 
into the tuber until they join the central cylinder, as well as 
the disposition of the bundles in the cylinder itself. 
The transition from stem to root in the hypocotyl has been 
described in very few Monocotyledons. In these plants it 
takes place as a rule with great abruptness, and it is hardly 
possible to prepare a series of transverse sections from which 
the course of the bundles in so short a region can be accurately 
determined, without the aid of a microtome. In his elaborate 
researches on the anatomy of this region in Vascular Plants, 
M. Gerard states that his choice of Monocotyledonous species 
was much limited by the necessity of using those only which 
possess a moderately long hypocotyl 1 . In fact, he described 
but nine species, nor has much been done in this direction 
since the publication of his paper in 1881. The anatomy of 
the hypocotyl in any Monocotyledon is therefore worth 
investigation. 
Course of the Bundles in the Stem. 
At the end of the first year, the three leaves which will 
come to maturity in the following season are fairly well 
differentiated in the stem-bud. But to understand the 
vascular system of the tuber we must choose a seedling in 
which the cotyledon is still present — such a specimen, for 
1 Gerard, Passage de la Racine a la Tige .... Ann. d. Sci. Nat., Ser. 6, 
Vol. xi, Bot., 1881. 
