CHAP. II. 
LEAVES. 
113 
The scar formed by the separation of a leaf from its stem 
is sometimes called the cicatricule. The withered remains of 
leaves, which, not being articulated with the stem, cannot fall 
off, but decay upon it, have been called reliqum or induvics, 
and the part so covered is said to be induviate. 
When leaves are placed in pairs on 
opposite sides of a stem {fig* 53.), and 
on the same plane, they are called op^ 
posite : if more than two are opposite, 
they then form what is called a whorl, 
or verticillus : but if they arise at re- 
gular distances from each other round 
the stem, and not from the same plane, 
they are then called alternate. 
In plants having Exogenous stems, 
the first leaves, — namely, those which 
are present in the embryo itself {cotyledons), — are uni- 
formly opposite ; but those subsequently developed are either 
opposite verticillate, or alternate in different species : on the 
contrary, in Endogens, the embryo leaf is either solitary, or, 
if there are two, they are alternate ; and those subsequently 
developed are usually alternate also, but few cases occurring 
in which they are opposite. Hence some have formed an 
opinion that the normal position of the leaves of Exogens is 
opposite, or verticillate ; and that when the leaves are alter- 
nate, this arises from the extension of a node ; while that of 
Endogens is alternate, the whorls being the result of the con- 
traction of internodes. 
But it seems more probable that the normal position of 
all leaves is alternate, and their position upon the stem an 
elongated spiral, as is in many cases exceedingly apparent, 
as, for instance, in the genus Pinus, in Pandanus, which is 
actually named Screw-pine, in consequence of the resem- 
blance its shoots bear to a screw, and in the Pine-apple : the 
Apple, the Pear, the Willow, the Oak, will also be found to 
indicate the same arrangement, which is only less apparent 
because of the distance between the leaves, and the irresfu- 
larity of their direction. If, in the Apple-tree for instance, a 
line be drawn from the base of one leaf to the base of another, 
I 
