om the seed in order to know that it had two seed
leaves; because the mature plant always shows certain characteristics
that accompany this condition of the seed.

In every plant having two seed leaves, the mature leaves are
netted-veined, which is a condition easily recognized even by the
layman; also the parts of the flowers are in circles containing two or
five parts, but never in threes or sixes. The stems of plants of this
class always increase in thickness by means of a layer of cells known as
a cambium, which is a tissue that continues to divide throughout its
whole existence. The fact that this cambium divides as long as it lives,
gives rise to a peculiar appearance in woody stems by which we can, on
looking at the stem of a tree of this type when it has been sawed
across, tell the age of the tree.

In the spring the cambium produces large open cells through which large
quantities of sap can run; in the fall it produces very thick-walled
cells, as there is not so much sap to be carried. Because these
thin-walled open cells of one spring are next to the thick-walled cells
of the last autumn, it is very easy to distinguish one year's growth
from the next; the marks so produced are called annual rings.

We have now classified coffee as far as the class; and so far we could
go if we had only the leaves and stem of the coffee plant. In order to
proceed farther, we must have the flowers of the plant, as botanical
classification goes from this point on the basis of the flowers. The
class _Dicotyledoneae_ is separated into sub-classes according to whether
the flower's corolla (the showy part of the flower which ordinarily
gives it its color) is all in one piece, or is divided into a number of
parts. The coffee flower is arranged with its corolla all in one piece,
forming a tube-shaped arrangement, and accordingly the coffee plant
belongs to the sub-class _Sympetalae_, or _Metachlamydeae_, which means
that its petals are united.

[Illustration: THE COFFEE TREE, SHOWING DETAILS OF FLOWERS AND FRUIT

From a drawing by Ch. Emonts in Jardin's _Le Cafeier et Le Cafe_]

The next step in classification is to place the plant in the proper
division under the sub-class, which is the order. Plants are separated
into orders according to their varied characteristics. The coffee plant
belongs to an order known as _Rubiales_. These orders are again divided
into families. Coffee is placed in the family _Rubiaceae_, or Madder
Famil