de Fraine .— The Seedling Structure of eertain Cadaceae. 155 
possession of three cotyledons subtending three tubercles. The behaviour 
of the vascular tissue points to the fact that two of the cotyledons (c v c 2 , 
Diagram 12, Fig. 1) have been derived from the splitting of one larger one 
to its extreme base. The three pairs of vascular strands run into the 
hypocotyl so very obliquely that it is impossible to say definitely exactly 
what occurs, but fusion of the members of a pair takes place, resulting in 
the formation of three bundles, as shown in Diagram 12, Figs. 1-3. 1 
The strand (c 3 + 4) which supplied the smaller cotyledon and its tubercle 
soon showed a bifurcation of the phloem (Diagram 12, Fig. 5), while 
the other two bundles rotated towards one another and together formed 
a V-shaped strand in which the protoxylem occupied the apex of the V. 
Large metaxylem tracheides were enclosed by the arms of the V; these, 
however, soon died out and others differentiated centripetally, as is shown 
in Diagram 12, Fig. 5. 
1 The elongation of the bundles shown in Diagram 12, Figs. 3 and 4, and in Diagram 13, Figs. 2 
and 3, is intended to represent their appearance in almost longitudinal section. This is due to the 
rapidity of their centripetal displacement. 
