48 
IOWA ACADEMY OP SCIENCE 
According to Winton and Hanausek the testa consists of six layers which 
they designate as: First, the outer epidermis with outer walls, greatly thick- 
ened and a laminated structure. Second, the hypodermal structure with greatly 
thickened pore walls. Third, the tube cells, a layer of loose tissue of two or 
three layers with rather thickened walls. Fourth, cross cells like the tube cells 
but with transversely elongated elements. Fifth, starch cells, thin walled cells 
which contain minute starch grains. . Sixth, the inner coat or inner epidermis, 
as they call it, this consists of transversely elongated cells with polygonal form 
and intercellular spaces absent. The coat is followed by the perisperm, endo- 
sperm, and embryo. 
Harz in his study of the fruit of Poterium and Sanguisorba indicates that 
the testa consists of elongated cells with fine granular contents, underneath 
the epidermas three or four rows of compressed cells, this represents probably 
the perisperm or the inner testa 
The endosperm consists of a single row of cells somewhat longer than broad, 
filled with granular material, the cells of the embryo in contact with the endo- 
sperm are isodiametric or sometimes a little longer than broad without palisade 
parenchyma. The palisade parenchyma occurs upon the upper face of the coty- 
ledons or where the two cotyledons meet. The embryo contains no starch, 
but an abundance of fat and protein. 
The seeds of Sanguisorba consist of the testa and endosperm and a probable 
remnant of the perisperm. The testa is thin without sclerenchyma elements, 
the outer rows consist of rather thin walled parenchyma cells, the two or three 
layers underneath are like it, but somewhat more compressed, underneath these 
larger elements the compressed elements which probably represent the perisperm 
or inner seed coat are found. The endosperm, like the preceding species. It 
appears from these studies of Harz that there are some radical differences be- 
tween the Proterium, Sanguisorba and Pyrus. The absence of the sclerenchyma 
in these genera is noteworthy. 
The Testa. The general characters of the seed may be gleaned from the 
following description from the Ben Davis apple. The testa is slightly irregular 
on the surface, the epidermal cells of the outer testa are thick walled and 
laminated. The walls swell somewhat on the addition of water. 
Sclerotic parenchyma. The sclerotic layer is somewhat variable as to the 
number of rows of cells, the number varies from fifteen to twenty, brown in 
■color. The cells are thick walled with pore canals, the lower portion of the 
^sclerotic parenchyma may possibly be differentiated into a distinct layer. Win- 
ton and Hanausek indicate tube cells and cross cells. The spongy parenchyma- 
like lower portion of the tube cells may be differentiated in some cases, we do 
not, however, consider that this is essentially different from the sclerotic paren- 
chyma. Most of the variation in varieties occurs in the epidermal and aclerotic 
layer, shown in sketches. 
Cross Cells. The cross cells are not always evident in sections of the apple 
seeds, but they are evident in the Baldwin and Iowa Blush apple seeds. 
Starch Cells. The starch cells consist of a single layer, of colorless thin 
walled cells filled with minute starch grains made very evident upon applica- 
tion of iodine to the section. The presence of starch here is very unusual in 
seeds. The cells of the inner seed coat are very much compressed, polygonal in 
outline. 
