Ranales ) Rhoeadales, and Rosales. 
725 
Pittosporaceae. 
Sollya heterophylla presents in the main the usual features of the diarch 
form, but with very characteristic details. Thus the primary xylem is 
distributed in the double bundle at the base of the cotyledons in an 
unusually definite T-shaped manner. The 
protoxylem is completely exarch, and the 
arm of the T composed of a single file of 
centripetally developed elements which spread 
out left and right inside the phloem groups. 
Pittosporum crassifolium. This species is 
noted for its polycotyledony. In the lower 
part of the hypocotyl are to be found four 
triad groups, which in the upper part pass 
out into the four cotyledons as their re- 
spective double bundles. The radial files of heterophylla. nat. size. 40, 
. Pittosporum crassifolium. \ nat. 
primary xylem are noticeable, but are not so s i ze . 
marked as in Sollya heterophylla. The hypo- 
cotyledonary strands are continued downwards into those of a tetrarch 
root. On the periphery of the bundles opposite the protoxylems large 
secretory sacs are to be found. 
In the tricotyledonary forms there is apparently fusion between two of 
the four vascular triads in the upper part of the hypocotyl, so that three 
double bundles pass out into the three cotyledons. 
Hamamelidaceae. 
Liquidambar styraciflua. The hypocotyl possesses the customary four 
strands. In the position usually occupied by the central protoxylem of the 
double bundle there is to be found a large secretory canal, so that the 
halves are completely separated from one another. In each cotyledon they 
form a double bundle only, differing from the usual arrangement in the 
presence of the large secretory canal in its centre, on either side of which 
a streak of crushed protoxylem is obvious. In the root the four xylem 
strands assume an even greater independence, each with a well-defined 
completely exarch protoxylem pole. Two phloem groups are present in the 
customary position^ viz. in the intercotyledonary plane, and if it were 
not for the secretory canal in the cotyledonary plane the root would 
doubtless be diarch. 
Platanaceae. 
Platanus occidentals and P. orientalis. The seedlings are remarkable 
for their slightness, in view of the habit of the adult plant. Although the 
root is ultimately diarch, the hypocotyl is characterized by the presence of 
3 c 2 
