STUDIES IN THE DEVELOPMENT OF THE PIPER ACEAE 723 
that this wall is composed of three carpels (figs. 36). This view is 
strengthened by the fact, that even when a larger number of 
stigmatic lobes is present, the structure of the wall lower down is 
like that of ovaries with three stigmas. For example, a transverse 
section nearer the base of the ovary from which the four stigmatic 
lobes in fig. 37 are taken, shows a structure exactly like that illus- 
trated in figs. 35 and 36, which latter figures are taken from an 
ovary with a distinctly three-lobed stigma. The number of vas- 
cular bundles in the wall of the ovary also indicates that it is made 
up of three carpels. All of this evidence supports the interpre- 
tation of the structure of the ovary given for the close relatives 
of Piper betel by Eichler (78, 2, fig. 4). 
From a very young stage of development of the flower, the tis- 
sues of the axis continue to expand radially on all sides, keeping 
pace with the elongation of the ovary. The result of this is that 
the cavity of the ovar}' becomes completely buried in the fleshy 
axis (figs. 4, 33, 44, 63, 68). Another result of this growth is that 
the stamens are carried outward, and often in the mature flower, 
seem to stand upon a mound of carpellary tissue (figs. 44, 45, 65). 
The structure of the ripe fruit of Piper betel differs markedly 
from that of Piper medium (Johnson, '02, p. 322, figs. 14, 15). 
In the first place, the immersion of the seed of P. betel in the axis 
leaves little of the tissue about it to be derived from the carpels 
proper. The latter apparently form only the roof of the ovarian 
cavity (figs. 65, 66). The three layers of the carpellary tissue of 
the fruit of P. medium are distinguishable in P. betel only at the 
upper end of the fruit. At the sides, and near the base, only the 
two inner layers are present. There are four vascular bundles 
running longitudinally in the outer of these two layers (fig. 67), 
instead of six as in P. medium. The oil-secreting cells are three 
or four layers thick in the upper third of the fruit (fig. 66), they 
form a single broken layer at the sides of the fruit, and become 
more numerous again at the base. The whole of the tissue sur- 
rounding the seed is relatively soft, and the seed apparently must 
be set free by the decay of these. 
While the normal course of development of the fruit in a female 
or hermaphrodite flower, is that just described, there are scattered 
