122 
Sargant . — The Reconstruction of a Race of 
highly differentiated group in the vegetable kingdom. Their classification 
has occupied many generations of botanists, and the result is no doubt 
in the main a truly natural system ; that is to say, a system based on real 
affinities. With such wealth of evidence to draw upon, we might expect to 
work backwards with certainty from the most primitive forms which we 
know to their common ancestors — a race which of course has been long 
extinct. But this is so far from being the case that authorities are still 
hopelessly divided on the interpretation of the facts. 
On the other side is all we know about the forms, living or extinct, 
which may have stood near the main line of Angiospermous descent. The 
difficulty in this case is want of evidence. The floral structure of Angio- 
sperms by itself isolates them from all other groups, without taking other 
characters into consideration. 
In the most recent attempt to reconstruct the pedigree of Angiosperms 
(Arber and Parkin, 4 , p. 77) 1 , the authors start from a Palaeozoic ancestor, 
which they place among the newly recognized group of Pteridosperms. 
They trace the development of the flower through a series of hypothetical 
forms — pro-anthostrobilus (p. 63, Fig. 4) ; eu-anthostrobilus (p. 44, Fig. 1) — 
up to the more complex form of Ranal flower, Magnolia or Liriodendron . 
While the female sporophyll of the pro-anthostrobilus is suggested by that 
of Cycas , the whole scheme of the fructification is intermediate between the 
Angiospermous flower, on the one hand, and the bisexual strobili described 
in the American Bennettiteae by Dr. Wieland, on the other. The eu- 
anthostrobilus makes a much nearer approach in detail to the Ranal 
type, considered by the authors as the most primitive form of flower now 
in existence. 
It will be seen that even this bare outline of a possible pedigree 
for Angiosperms depends largely on two recent additions to our know- 
ledge : on the recognition of the Pteridosperms as a group of primitive seed- 
plants, and on the description of bisexual strobili among the Bennettiteae. 
The memoir ( 4 ) was not published in full until July, 1907, but it was 
communicated to the Linnaean Society at the meeting on March 21 of that 
year, when the authors read an abstract which gave rise to a discussion on 
the Origin of Angiosperms ( 3 , p. 13). 
On the earlier date I was still engaged in preparing a course of lectures 
on the Ancestry of Angiosperms, which were delivered for the London 
University in May and June, 1907. The aim of the course was to re- 
construct the common stock from which I assumed Monocotyledons and 
Dicotyledons to be descended. This stock was referred to as the Primitive 
Angiosperm. The subject proved sufficient to occupy eight lectures without 
entering at any length into the vexed question of the primitive flower. 
1 The Table of Relationships here quoted is reproduced, by kind permission of the authors, on 
p. 137 of this memoir. 
