founded on the Structure of their Seedlings . 47 
These considerations lead to the conclusion that Anthurium 
must be held a more primitive type than Arum or Arisaema. 
Palmae. 
A number of young Palm seedlings were included in the 
Kew collection, and of these I have examined nine species. 
In three of them my observations are very incomplete, owing 
partly to a want of material at the proper age, and partly to 
difficulties of manipulation. The vascular structure of young 
Palms has often to be worked out by hand sections only, as 
the woody tissues of the axis do not embed well in paraffin. 
Good microtome series have, however, been cut through 
the hypocotyls of Desmoncus minor, Thrinax excetsa, Areca 
sapida , and Phoenix dactylifera , and hand sections have given 
goods results in two other species, Desmoncus sp. and Acantho- 
phoenix crinita. I can give a fairly complete account of the 
vascular system in the seedlings of these six species, though 
even here the details are commonly obscured by the massive 
development of the plumular traces due to the comparatively 
advanced age of the seedlings. 
The external characters of all the Palm seedlings I have 
seen are much modified from the ordinary monocotylecjonous 
type by the arborescent habit of the family, and their internal 
structure is not less profoundly affected. The first leaves 
are developed early. Their tissues are hard and woody from 
the first, owing to the number of vascular bundles developed 
within them and the stiffening of those bundles by massive 
sclerenchymatous sheaths. The primary root is always pretty 
well developed, and is sometimes the main root for a long 
time {Thrinax excetsa, Chamaerops humitis). In other species 
it is soon surpassed in length and thickness by the first cauline 
root. The vascular system of the latter is commonly the 
direct prolongation of plumular traces, as that of the primary 
root is of cotyledonary traces. 
The tip of the cotyledon is merely a sucking organ, which 
for many months after germination continues to supply the 
seedling with nourishment from the stores laid up in the 
