Hill — On the See d ling- S true hire of certain Piper ales. 173 
considerably in the same family or genus. He also states his opinion that 
the Piperales are not very primitive, and that, in all probability, their 
nearest relations are to be found in those cohorts characterized by the 
presence of perisperm, viz. the Aristolochiales, Polygonales, Centrospet- 
males, and the Ranales. 
However this may be, and much may be said against the view here 
expressed, the facts relating to the structure of the seedlings strongly 
confirm Johnson’s hypothesis 1 , and, without expressing an opinion upon 
the relative primitiveness of the order, the writer is in full accord with 
this view that Peperomia is a reduced genus. And this opinion is, in the 
case of Peperomia pellncida , much strengthened by the fact that ‘the 
embryo remains very small and shows no differentiation when the seed 
is ripe ’, 2 which, in the opinion of the present writer, more than counter- 
balances the increase in the number of the constituent parts in the embryo-sac. 
If, then, Peperomia be a reduced form, what is the factor which has 
brought about the reduction ? 
Both Campbell 3 and Johnson 1 have apparently recognized what 
Tansley 4 afterwards expressed, viz., that in the apparent absence of some 
cause to which the reduction may be ascribed, ‘ the hypotheses of relative 
primitiveness and of reduction do not stand on an equal footing. The 
former has the logically prior claim, and must be accepted as a working 
theory until good grounds can be given for preferring the latter.’ 
Johnson 5 suggests that the peculiarities of Peperomia are analogous to 
those found in many aquatic, parasitic, and saprophytic Angiosperms ; in 
reply to which, Campbell 6 remarks that ‘the habit of the plant in question 
conforms to neither of these forms, i. e. there is nothing to account for the 
reduction.’ 
The present writer suggests that the determining factor which has 
brought about the reduction may be found in the epiphytic habit of many 
of the forms. 
The second feature of theoretical interest is the bearing of the facts 
described upon some of the current and possible hypotheses relating to the 
phylogeny of the Angiosperms. Briefly, these theories are as follows : — 
1. The Dicotyledons have arisen from the Gymnosperms. 
2. Of the Angiosperms, the Dicotyledons are the more ancient group, 
and have given origin, through the Ranunculaceae, to Monocotyledons. 
3. The Monocotyledons have given rise to the Dicotyledons, the 
connexion being through the Araceae and the Piperaceae. 
4. Further, if it be held that the single seed-leaf has been formed by 
1 Bot. Gaz., xxx, 1900. 
3 Campbell. The Embryo-sac of Peperomia. Ann. Bot., xv, p. 112, 1901. 
* Loc. cit. 
* Tansley, A. G. Reduction in Descent. New Phytologist, Vol. i, p. 131, 1902. 
5 Loc. cit. 15 Loc. cit. 
