ii 6 Campbell . — The Embryo-Sac of Peperomia. 
at the antipodal end is correlated with the marked polarity 
of the embryo-sac structures. In short, both antipodal cells 
and endosperm are equally of prothallial nature. 
From a study of the condition of things in Peperomia , there 
is not the slightest evidence either that the antipodal group 
of the typical embryo-sac represents a second egg-apparatus, 
or that the polar nuclei are sexual in their nature. 
The Systematic Position of Peperomia. 
Through the kindness of Dr. D. H. Scott, several species 
of Peperomia were germinated at Kew, and an examination 
of these showed them to be true Dicotyledons — of which 
group Peperomia may be considered to be the most 
primitive type. 
The reasons for this conclusion lie of course mainly in the 
character of the embryo-sac and the extremely simple flowers ; 
but there are other features which point to this genus as 
a primitive generalized type. Peperomia shows several signi- 
ficant resemblances to the lower Monocotyledons, especially 
the Araceae, which themselves give evidence of being a very 
low type. The structure' of the flowers, and their arrange- 
ment upon a thick spike, in many species quite like a true 
spadix, is noteworthy, while the habit of the plant, the form 
of the leaves, and the arrangement in the stem of the vascular 
bundles recalls very strongly the structure of the Araceae. 
Moreover, the endosperm-formation is very similar in the 
two, being by direct division. 
The relation of Peperomia to the other Piperaceae is unmis- 
takable, and it is to be hoped that further investigations of 
members of this family may reveal some intermediate forms. 
The Saururaceae seem to represent a distinctly more specialized 
type than the Piperaceae, from which they have probably 
been derived. There seems no valid ground for supposing 
that the reverse is the case, as has been assumed by Engler 1 , 
Engler, Piperaceae, Die nat. Pflanzenfamilien, iii. Th., i. Abt., 1899. 
