THE. ROYAL FAMILIES OF PLANTS. 473 
that in a well-filled pod of peas, about four are found 
growing on one side, and as many on the other. This is 
the structure of the legume, or simple pod. Possibly it 
appears, in some instances, outside the royal family ; but 
very rarely, indeed, if ever. It is not like the pods of the 
Mustard and Gilliflower, for they have a partition running 
through them flatwise, and the seeds hang upon both 
Seams instead of one. The pods of the Milkweeds are 
very different, again, being mere bags in which the seeds 
are enclosed without the least attachment to any part, but 
grow upon the end of the stem where it passes into the 
interior. The simple pod, or legume, then, is the second 
mark of the Pisids, and any one can tell it at a glance. 
The third mark is simple, curious, and infallible, to the 
highest degree. The family most likely to be confounded 
With these is that to which the Rose and the Apple be- 
long; in fact, though we might not expect it, the two run 
So closely together, that only this third mark is decisive 
as between them. And yet, all-important as it is, it 
seems the merest trifle. Look at the bottom of the Pea- 
flower, outside. There are five small, green, pointed 
leaves surrounding it, that together are called the calyx, 
and severally are termed sepals. Now find a flower that 
grows pretty low down on the stem,—from the angle of 
a leaf perhaps, —and carefully lift it up against the stem 
without giving it any twist one way or the other. Thus 
you bring the real top of the flower to the stem. Notice, 
now, that if you have worked fairly the stem comes, not 
against one of the green sepals, but into the notch or 
Space between the upper two of them. The odd sepal, so 
to speak, is on the outer or lower side. If we had taken 
aà rose or an apple-blossom or the flower of a Spiræa, and 
80 examined it, we should have met just the reverse ; the 
AMERICAN NAT., VOL. I. 
