19 
In a radial section (Fig. 2, II) the crystals, which are often 
twinned, fill more or less completely the I-shaped cavity, which is 
almost obliterated by the swollen lateral walls where it is not dis- 
tended by them. 
The cells of the third layer are elongated laterally, are 
thin-walled and separated by numerous intercellular spaces. In 
a tangential section they are star-shaped. The cell cavities 
are filled with fine granular protoplasm. Some of these cells in 
the colored varieties contain pigment. 
The cells of the fourth layer are elongated laterally and 
are also thin-walled; they differ from those of the third layer in 
that the cells are longer and larger. In colored varieties some of 
these cells contain pigment. The fibro-vascular elements are 
present in this layer. 
The cells of the last layer are very compact and appear small 
in a radial section. However, their true structure can only be de- 
termined ina tangential section, when the cells are seen to resemble 
somewhat the star-shaped cells of the third layer, but they differ 
from those in that they are more dichotomously branched. The 
cell contents are made up of fine, granular protoplasm. 
THE KENTUCKY COFFEE BEAN (Gymnocladus Canadensis, 
Lam.)—The seed of the Kentucky Coffee Tree is anatropous and 
has a straight embryo. With a small magnifying glass there can 
be readily distinguished three distinct layersin the seed-coats. 
The innermost of these is the thickest and darkest layer (Fig. 5). 
On the upper flattened side it generally diminishes in thickness 
as it approaches the poles of the seed. Above the palisade layer 
is the rather thickened cuticle, which has a tendency to separate 
from the palisade cells. This layer when macerated in water and 
allowed to stand, sometimes breaks up into small pieces and sep- 
arates from the remaining part of the seed-coat. It is then some- 
what mucilaginous. Ina surface view the palisade cells are much 
the same as in Phaseolus, excepting that the central cavity (Fig. 
6) is greatly enlarged and the folds are less distinct and marked 
as regards their branching. Ina cross section (Fig. 7) six well- 
defined layers may be distinguished. I. The palisade layer. II. 
A layer of I-shaped cells. III. A layer of sclerenchyma. IV. 
A layer carrying pigment. V. A layer of vessels and thick-walled _ 
* 
