4 2 Sargant. — T heory of the Origin of Monocotyledons 
containing three or four traces from the cotyledon, and these 
retain their stem-structure for some distance downwards. In 
one seedling I found six traces, for two entered it from the 
plumule, but this is exceptional. As a rule, a portion of 
each plumular trace is inserted on the ring of cotyledonary 
traces at the first node, without altering the symmetry of the 
transition, but the rest of the plumular stele is continued 
directly downwards, and becomes the stele of the first cauline 
root. 
The structure of cotyledon and hypocotyl in A. Rovelliana 
seems essentially the same as that of A. spicata . 
Doryanthes Palmeri The seedling is very stout and fleshy. 
The first leaf is rolled upon itself, and forms a trumpet-shaped 
cylinder which is in a straight line with the hypocotyl and 
primary root. The cotyledon projects horizontally from the 
axis. Its blade is a flat, thick disc, covered for some time by 
the brown seed-coats. It is attached to a very short petiole 
which clasps the axis with its massive sheath. 
There are four main veins in the cotyledon, and they all 
enter the axis through the petiole. The plumular bundles 
form a ring of eight traces, which are joined at the node by 
the four traces from the cotyledon. These enter the stele in 
pairs, each pair displacing one of the plumular traces. 
The stele of the hypocotyl now contains ten distinct bundles. 
Within this circle are the two plumular traces displaced by 
the entrance of the cotyledonary traces. The displaced traces 
are not adjacent to each other, but separated by two others 
in the original circle of eight, and with these two they now 
unite. 
The hypocotyl in this species is comparatively long, 3 mm., 
even in quite young seedlings. The transition from a ring 
of ten stem-bundles to a 10-arch root-stele takes place 
gradually by branching and rotation of the xylem groups only — 
Van Tieghem’s type 1. 
The seedling of D. excelsa resembles that of D. Palmeri 
both in its external characters and its vascular symmetry. 
