156 FIsHER: SEED DEVELOPMENT IN THE GENUS PEPEROMIA 
pistil, which is sessile in the axil of a short, club-shaped, hairy 
bract. At the apex of the ovary there are three short spreading 
stigmas, and this indicates that the pistil is compound, consisting 
in its morphological origin of three carpels. In each ovary there 
is borne a single, orthotropous ovule with two integuments (FIG. 
41). The anthers are four-locular. There is no evidence—not 
even rudiments—of calyx or corolla. The flowers are borne on 
long slender spikes, which bear a close resemblance to those of 
many Peperomias. 
The flowers are closely crowded on the spike. While it 1s 
true that they are initiated acropetally, they do not reach maturity 
in this succession, but all mature at practically the same time. 
In this latter particular they differ from those of the genus 
Peperomia. 
The development of the embryo sac in Piper tuberculatum is — 
closely similar to that described by Johnson (32 and 35) for Piper 
medium, Piper umbellata, and Piper Betle var. monoicum. 
The primary archesporial cell is single and it is subepidermal 
(Fic. 37). This cell divides transversely, the upper cell being 4 
parietal or tapetal cell, and the lower cell being the definitive 
archesporial cell (Fic. 38). The parietal or tapetal cell divides 
to form a layer four or five cells thick in the mature nucellus. 
The definitive archesporial cell develops.directly into the embryo 
sac, without cutting off any megaspores. 
The nucleus of the definitive archesporial cell, or embryo sac 
mother-cell (Fic. 39), divides to two (Fics. 40, 41), and these two 
divide to four nuclei (Fic. 42). These divisions are not followed 
by walls, even evanescent ones. The nuclei of the embryo sac 
at the four-nucleate stage always have the linear arrangement or a 
close approach to it (Fic. 42). Not a single case of tetrahedral 
arrangement, as is found in Peperomia, was observed. Each 0 
the four nuclei divides once more, giving rise to an eight-nucleate 
embryo sac, which contains an egg, two synergids, two polar 
nuclei, and three antipodals (Fic. 43). Thus it very closely 
resembles those found in other species of Piper and is typical 
of those found in the vast majority of angiosperms which have 
been investigated. There is some evidence that one of the male 
nuclei takes part in the formation of the endosperm nucleus. 
[To be concluded] ; 
