130 AMERICAN MIDLAND NATURALIST 
leaves, and is almost as striking as the well-known heterophylly in 
' Sassafras, where lobed and entire leaves appear on the same shoot 
with no indication of any special arrangement. So far as concerns 
our Nyssa I can only say that the dentate leaves occur occasionally 
on the seedlings during the first season, that they are very frequent 
on the young shrubs, where they are equally as common on the long, 
vigorous shoots as on the short, lateral branches of these; but, so 
far, I have not observed any such dentation of the leaves on the 
root-shoots of Nyssa. The accompanying figures 3-6 illustrate the 
foliage of a single lateral branch, of which figure 3 shows the basal, 
figure 6 the apical of these leaves; figure 7 represents a larger leaf 
from a tall shrub, and the dentation is very pronounced. It gen- 
erally appears as if the dentate leaves are larger than the entire; it 
is, for instance, not uncommon to find dentate leaves measuring 
up to fifteencm in length, while the entire on the same branch may 
reach only nine or ten cm, or much less. Another point, not to be 
left out of consideration, is the noticeable difference in outline be- 
tween these two types of leaves. While the dentate are always 
obovate, the entire vary from lanceolate to oval, obovate, the oval 
being perhaps the most frequent of the mature tree, and the obovate 
that of the seedling. 
In passing to describe the internal structure of the vegetative 
organs as observed in Nyssa sylvatica, it must be stated beforehand 
that the stem and leaves of the Cornaceae have already been studied 
by various authors, while the root, as is generally the case, has been 
neglected. A very complete treatment of the family from an 
anatomical point of view has been presented by Solereder in his 
work, „Systematische Anatomie der Dicotyledonen.* In this 
treatment, however, the leaf and the stem of the mature tree only 
have been examined, thus we conceive no comparison between the 
various stages of growth, and no information about the root- 
structure. The ample material which I have had the opportunity 
to study enables me to present some supplementary notes, beside a 
description of the root-system as represented in the giing and 
mature tree. Let us begin with the root. 
THE ROOT. 
-So long as the cotyledons are the only leaves developed upon 
the seedling the primary root shows a very simple structure, and 
* Stuttgart 1899 page 487. 
