3 2 ° 
Lee. — Observations on the 
approximately parallel with the midrib, and like the latter joins the lateral 
strands at the apex. Smaller branches are also given off by all these 
bundles. The character seen in most of the Compositae examined, i. e. 
fusion of the chief bundles at the apex of the cotyledon, is easily 
demonstrated in this species. 
The transition is much like that seen in Charieis heterophylla. The 
xylem of the lateral strands remains distinct in the centre of the hypocotyl 
for a long distance before finally merging into the xylem of the midrib 
bundles to form the diarch plate. 
Saussurea albescens , Hook. Seedlings 6-9 cm. long, and rather 
massive. The internal morphology is very similar to that in Silybium 
Marianum , the chief difference being that here the transition begins at a 
high level. In the midrib bundles the phloem bifurcates, and the 
protoxylem becomes exarch while still in the cotyledons. 
Onopordon tauricum , Willd. Seedlings very large, with ovate and 
equal cotyledons which join at the base to form a large cotyledonary tube. 
The transition is almost exactly as in Tridax procnmbens , a diarch root 
being produced: 
Crupina Crupinastrum , Vis. In this species the seedling is similar in 
size and external morphology to that of Silybium Marianum , and differs 
from the latter only in a few particulars with regard to transition. In both 
there are five strands at the base of the cotyledon. The extreme laterals 
from one cotyledon fuse with the corresponding bundles from the other as 
soon as the cotyledonary tube is reached. The fused structure, instead of 
moving round in a clockwise manner as in Silybium Marianum , passes 
inwards, and is joined by the remaining lateral strands on the same side, 
the three fusing together. All this occurs in the cotyledonary tube, so that 
only two bundles in addition to the two midribs enter the hypocotyl. These 
four strands, of which the intercotyledonary ones are the smaller, are 
symmetrically arranged. In the midrib the bundles become tangentially 
flattened, and gradually the protoxylem takes up an exarch position. In 
the intercotyledonary bundles the phloem, also, spreads out and is joined 
by the bifurcations of the midrib phloem. At a lower level, the xylem of 
these bundles gradually decreases in size and passes inwards. Near the 
centre it is joined by the xylem from the cotyledonary plane, with which 
it fuses, producing a diarch root. 
It should be noted that here, though the arrangement in the hypocotyl 
suggests a tetrarch root-structure, the latter is never attained. In the 
intercotyledonary strands the xylem never becomes exarch, and the phloem, 
though assuming a flat ribbon-like form, never bifurcates. 
Amberboa ( Volutarella ) muricata , DC. Seedlings 4 -6 cm. long, and 
with comparatively fleshy seed-leaves. The transition is similar to that in 
Crepis rubra. 
