18 
of my own examination, though agreeing in general with his 
statements, is given to facilitate comparison when the other seeds 
are described : 
THE COMMON GARDEN BEAN (Phaseolus vulgaris, Savi.)— 
In the seed-coats of the common garden bean there are five well- 
marked layers: I. The palisade layer. II. The crystal layer. III. A 
layer of simple parenchyma. IV. A layer in which the fibro- 
vascular elements are found, surrounded by parenchyma. V. A 
layer of very compact branched cells. 
The cuticle covering the palisade cells, as described by Haber- 
landt, is very hard to distinguish because of its tenuity and the 
difficulty involved in getting sections which are thin enough, 
while in some varieties it has a tendency to flake off. 
The prismatic palisade cells are five, six or more sided, and 
in a surface view show a branched cell cavity (Fig. 1). In a cross 
section of the seed-coats (Fig. 2) the cells are seen to be greatly 
elongated radially. The central cell cavity, which is somewhat 
widened at the base, extends nearly the entire length of the cell 
to the cuticle (Fig 3).+ Asa consequence of this gradual widening, 
the lateral walls gradually become thinner towards the base (Figs. 
3 and 4). 
In an isolated palisade cell, macerated in concentrated potash, 
or in Schultze’s medium, the structure of the folds and the cell 
cavity are more clearly indicated, as shown in Figs. 3 and 4. 
In the colored varieties of Phaseolus, the cell cavities are 
filled with a pigment. The narrow “light line” runs close under 
the cuticle (Fig. 2, 1*.)t 
In a surface view the cells of the second layer are five or 
six sided, very thick-walled, and the cavity appears to be filled 
with a crystal of calcium oxalate.§ eo 
*G, Haberlandt, Ueber die Entwickelungsgeschichte und den Bau der Samenschale 
bei der Gattung Phaseo/us. Separat abdruck aus den Sitzungsbericht der Kais. Akad. 
der Wiss. ; Wien, 1877, Ixxvi., I. Abth. 
tThere are some apparent exceptions to this, as in some cases this portion of the 
cavity seemed only to extend up about one-third of the distance. 
} Sicyos angudatus is said to have peculiar refractive portions so characteristic of 
ica they are present in the third layer. (See Fickel, 1. c., p. 11, Plate 
ay Pig. 22, 
§in some of the varieties of Phaseolus vulgaris the cells present a different appear 
ance, since they do not contain crystals. The inner layer ot parenchyma cells in the 
seed-coats of Sicyos angulatus contain, according to Fickel (1. c., p. 11) crystals of 
calcium oxalate in the course of their development, but these disappear when the seed 
has fully ripened. 
