re angular.

The coffee bean with which the consumer is familiar is only a small part
of the fruit. The fruit, which is the size of a small cherry, has, like
the cherry, an outer fleshy portion called the pericarp. Beneath this is
a part like tissue paper, spoken of technically as the parchment, but
known scientifically as the endocarp. Next in position to this, and
covering the seed, is the so-called spermoderm, which means the seed
skin, referred to in the trade as the silver skin. Small portions of
this silver skin are always to be found in the cleft of the coffee bean.

The coffee bean is the embryo and its food supply; the embryo is that
part of the seed which, when supplied with food and moisture, develops
into a new plant. The embryo of the coffee is very minute (Fig. 331,
II, _Em_)[101]; and the greater part of the seed is taken up by the food
supply, consisting of hard and soft endosperm (Fig. 331, I and II, _Sa_,
_Sp_). The minute embryo consists of two small thick leaves, the
cotyledons (Fig. 331, III, _cot_), a short stem, invisible in the
undissected embryo, and a small root, the radicle (Fig. 331, III,
_rad_).

[Illustration: Fig. 332. Coffee. Cross section of bean showing folded
endosperm with hard and soft tissues. x6. (Moeller)]

_Fruit Structure_

In order to examine the structure of these layers of the fruit under the
microscope, it is necessary to use the pericarp dry, as it is not easily
obtainable in its natural condition. If desired, an alcoholic specimen
may be used, but it has been found that the dry method gives more
satisfactory results. The dried pericarp is about 0.5 mm thick. Great
difficulty is experienced in cutting microtome sections of pericarp when
the specimen is embedded in paraffin, because the outer layers are soft
and the endocarp is hard, and the two parts of the section separate at
this point. To overcome this, the sections might also be embedded in
celloidin. When the sections are satisfactory, they may be stained with
any of the double stains ordinarily used in the study of plant
histology.

[Illustration: Fig. 333. Coffee. Cross section of hull and bean.
Pericarp consists of: 1, epicarp; 2-3, layers of mesocarp, with 4,
fibro-vascular bundle; 5, palisade layer; and 6, endocarp; _ss_,
spermoderm, consists of 8, sclerenchyma, and 9, parenchyma; _End_,
endosperm (Tschirch and Oesterle)]

A section cut crosswise through the entire fruit would present the
appearance sho