si) Sh a ee i aaa a a eer Bl ees ee eae bs ees ek 
1900] ENDOSPERM AND EMBRYO OF PEPEROMIA 7 
testa. All the walls of the cells of the outer layer become 
thickened till the cell cavity is practically obliterated, and the 
thickness of this layer is about the same over the whole of the 
seed, or slightly greater toward the base (int, figs. 14, 15). 
The cells of the inner layer thicken the outer walls greatly, 
especially near the upper end of the seed, where large knobs of 
the thickening substance project into the cell cavity (én, figs. 
14,15). The cavity is never entirely filled as in the outer cells, 
but considerable space remains which is packed with starch like 
the cells of the perisperm (7, figs. 14, 15). The innermost 
layer of thickening substance of the outer walls of the cells of 
this layer is of quite different consistency from the rest of the 
wall, and shows in sections as a uniform border about all the 
hollows and projections of the latter. 
At the base of the seed several layers of cells of the chalaza 
thicken their walls, like those of the outer integument layer, to 
complete the protection of the seed (jig. 74). 
The seed does not escape from the carpel, but the latter 
apparently remains adhering closely to it when the whole falls 
from the mother plant. At this time the carpel is four or five 
layers thick, except at the base and in the stigmatic region (cf, 
fig. 15). The outer layer is of large, cuboidal, nearly empty 
cells, interspersed with knob-like hydathodes. Its cells have 
unthickened walls, except for the fine striae found quite generally 
on the outer epidermal walls of the whole inflorescence (¢, fig. 
75). Next within this layer we find two or three layers of thin- 
walled flattened cells, with little contents. Closely adherent to the 
integument is the inner layer of the carpel, made up of large 
cells of about equal height and meridional length, but elongated 
equatorially to twice this length. These cells have the basal 
wall considerably thickened, with comparatively low ridges pro- 
jecting above this general thickening (fig. 75). The lateral and 
outer walls of these cells have anastomosing ribs surrounding 
thin spots or pits, forming cells closely resembling those of the 
velamen of the roots of many epiphytes in structure, and per- 
haps in function also. The basal or inner end of these cells is 
