OUTLINE OF STRUCTURAL BOTANY 49 
which are set free by the bursting of the wall of the parent cell. 
This separating the seed-bearing from the non-seed bearing plants 
constitutes a natural and to a great extent a definite division. 
Taking now the plants which are developed from seeds we find 
certain very general features which are characteristic of large 
groups. Thus, in a great class of seed-bearing plants the seeds are 
borne within a closed cavity; for example, the seeds of the pea-vine 
are enclosed within the pod, those of the rose within the rounded 
red fruit and those of the portulaca in a round capsule. On the 
other hand, if we examine one of the “cones” from a pine tree 
we find, on separating the more or less woody scales of which it is 
composed, the seeds lying between these scales not enclosed in a 
protecting chamber. This character prevails with all the species 
of pines, spruces and the like and seems to be an extremely old 
form of seed growth, for it is frequently found among the fossils 
of the carboniferous age. 
This contrast between plants bearing seeds in an enclosed cham- 
ber and those plants bearing seeds not enclosed has been taken 
by botanists as the first line of division, and we have the First 
Division of embryo-bearing plants consisting of those with the 
seeds not enclosed, naked seeded, and a Second Division, including 
all those whose seeds are enclosed within a chamber and these two 
great divisions include all the embryo-bearing plants. Hence we 
have reached the first step in Classification. 
Although the Gymnosperms are divided into a number of groups 
all of the species in our northeastern States belong to a single class, 
the Coniferae. 
A difference in the construction of the seeds leads to two great 
classes among the Angiosperms or plants whose seeds are protected 
within an ovary. 
If a grain of wheat, or a seed from some other grassy plant, and 
a garden bean or pea are placed in water for a few hours the outer 
covering or integument can then be easily removed, when it will be 
seen that the two kinds of seeds act quite differently, that in case of 
the bean or pea the seed easily divides into two principal lobes 
between which lies a small leaf-like object, the embryo, while in the 
case of the wheat kernel no such division occurs, but the embryo 
lies curled at the base of the single lobe. The two larger parts in 
the case of the bean and the one principal mass in the case of the 
wheat are the lobes, or technically the cotyledons, which are 
masses of nutriment stored up for the ‘support of the embryo 
until it can draw its own subsistence from the soil. 
The single lobe, with the embryo attached, the single cotyledon 
