182 
Sargant . — The Reconstruction of a Race of 
In addition to the Monocotyledonous characters already mentioned, 
Podophyllum peltatum has a 6-partite perianth. 
The partial fusion of the cotyledons and the anatomy of the erect stem 
in P. peltatum can be fairly interpreted as adaptations to a geophilous 
habit. A Ranal stock with similar characters, if exposed to more stringent 
conditions of the same kind, might easily go on to complete fusion of the 
cotyledons. It might not develop the lateral underground shoots which 
enable P. peltatum to spread in its swampy habitat, but the squat under- 
ground axis would probably be enlarged into a tuber with a fresh crop of 
root, each season. The aerial shoots would certainly be reduced in size. 
Such a form would not be far removed from a true Monocotyledon. 
Several objections to the geophilous origin of Monocotyledons which 
have been urged, or have occurred to me independently, may be considered 
here. 
It has been suggested that so large a class as Monocotyledons, and 
one so varied in habit, is not likely to spring from a race of plants so highly 
specialized to peculiar conditions. A plant may, however, be distinctly 
geophilous without being so completely adapted to its immediate surround- 
ings that its descendants can never change their habit. The geophilous 
primary axis of Podophyllum peltatum has not prevented it from acquiring 
the rhizome suited to a swampy station. Indeed, a geophyte which has not 
developed a pronounced tuber or bulb can readily adapt itself to an aquatic 
life. Its underground stem roots first in the muddy banks, and thence 
advances into the bed of a pond or stream. In the course of generations 
its aerial shoots become more and more adapted to submersion. Many 
comparatively ancient Monocotyledons, such as Alisma , have perhaps 
escaped extinction by taking possession of such situations. 
Climbers, again, often possess massive underground stems from which 
aerial shoots are sent up every year ( Bryonia , Tamus). 
The geophilous structure of the stem is certainly unfavourable to the 
evolution of trees. This is perhaps the line in which Monocotyledons 
are least successful. No Monocotyledonous tree can compete with Dico- 
tyledons outside the tropics. Within them, Palms have contrived to over- 
come the disadvantages of an essentially geophilous structure. The early 
growth of Palms, the slow formation of their axis in their early years 
by the addition of one disk after another to a squat subterranean stem, the 
close connexion of the early leaves with their special roots, all point clearly 
to a geophilous period in the history of the race (cf. Sargant, 73 , p. 344). 
The conditions of life which encourage geophilous characters are very 
local at the present time. Alpine summits are necessarily isolated : dry 
climates with periodic rains occur in limited regions scattered all over the 
globe. It is certainly difficult to conceive how a race formed in any one 
