294 Varietäten, Descendenz, Hybriden. 
Angiosperms. (Ann. of Bot. Vol XXII, p. 121 —186 with 21 text- 
figures 1908.) 
The Origin of Angiosperms is perhaps the most important Pro¬ 
blem which botanical morpholog 3 T has } T et to solve. Lately new facts 
have been contributed to the scanty evidence available, especially as 
regards the origin and development of the embryosac of Angiosperms 
and Gymnosperms, — the structure of Angiospermous seedlings — 
and the morpholog 3 T of the bisexual strobili of the American Bennet- 
titeae , which offer so man 3 T points of resemblance to the flowers of 
Angiosperms. Several authors have attempted to collect and piece 
together such evidence as now exists, especialty Coulter andCham- 
berlain, Hallier, Arber and Parkin. The most recent attempt to 
reconstruct the pedigree of Angiosperms is that of Arber and Parkin. 
The 3 T start from a Palaeozoic ancestor which the 3 T place among the 
Pteridosperms. The 3 7 trace the development of the flower through a 
series of h 3 T pothetical forms, — pro-anthostrobilus; eu-anthostrobilus 
— up to the more complex form of Ranal flower, Magnolia or Lirio- 
dendron. While the female sporoplwll of the pro-anthostrobilus is 
suggested b 3 T that of CycaSj 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 b 3 T 
D. Wieland on the other. The eu-anthostrobilus makes a much 
nearer approach in detail to the Ranal t 3 T pe, considered b 3 T the authors 
as the most primitive from of flower now in existence. They regard 
all other floral t 3 T pes as derived b 3 T reduction from this. Miss Sargant 
is in complete agreement with the general conclusions reached b 3 T 
Arber and Parkin, and attempts no separate reconstruction of the 
flower of the Primitive Angiosperms. She concludes that the strobiloid 
theory of the flower seems in the present state of our knowledge 
to stand alone as a working h 3 "pothesis. If we reject it we are lett 
without an 3 T historical clue to the origin of the floral structure of 
Angiosperms. 
Before discussing the evidence on which we ma 3 T hope to recon¬ 
struct the latest ancestor which Monocot 3 T ledons and Dicotyledons 
had in common, we must consider the question, Do all our living 
Angiosperms spring from a common stock? The argument in favour 
of the monoph 3 fletic origin of Angiosperms, which appears to the 
author to be conclusive, may be summarised as follows: the characters 
which Monocotyledons and Dicot 3 T ledons have in common are too 
numerous and too uniform to have been acquired independentK T 
in response to similar conditions. The 3 T must be derived by inheri- 
tance from a common stock. Assuming the truth of this Iwpothesis 
we are next confronted with the question of the comparative anti- 
quit 3 " of Monocot 3 Tedons and Dicot 3 Tedons. For a long time the pre- 
valent opinion was that Monocot 3 T ledons were older than Dicotyledons. 
Evidence in favour of this view was derived from three sources 1. 
the succession of fossil forms, 2. the comparative anatom 3 T of the 
stem, 3. the development of the embnm within the embr 3 r o sac. 
The fossil argument was founded on a mistake. It is now generally 
acknowledged that Monocotyledons do not appear before Dicot 3 T ledons. 
Neither does the argument from stem-structure hold good, for com- 
parison of seedling anaton^ in the two classes leads to the conclu- 
sion that the dicot 3 T ledonous stem-structure is primitive and the 
monocot 3 T ledonous derived from it. This conclusion agrees with that 
founded on the comparison of the mature stem anatom 3 r in both classes 
with that of other groups, living and extinct. The argument from 
