1904] SARGANT: EVOLUTION OF MONOCOTYLEDONS 3355 
During the winter of temperate, alpine, or arctic climates, during 
the prolonged drought of regions with a periodical dry season, 
such plants lose all their aerial organs and are left with the 
underground stock only. This is commonly a squat axis with 
roots and foliage buds—perhaps flower buds also—attached to 
it. A store of nourishment is always laid up in some part of 
this subterranean structure, as a rule in the enlarged stem. 
The more rigorous the conditions, the more pronounced the 
adaptations to them. When the growing season is short, the 
flower of a geophyte often comes up with or before the leaves. 
No part of the genial weather is then lost with regard to the 
formation and ripening of the seed. When once ripe, the seed 
fears neither frost nor drought, but the seedling is less hardy. 
The great problem before a seedling which germinates under 
such conditions is how in the course of the short growing season 
it may best prepare to face the rigor of the coming months. Its 
first care is to form an underground storehouse in the shape of a 
swollen stem or root to which the food packed in the seed may 
be transferred. This store of food is plunged in the soil, at first 
by the downward growth of the seedling as it leaves the seed coats, 
and later by the contraction of the root system which drags the 
tuber lower still.79 
In some species this is all that the seedling accomplishes in 
its first season (Arum, Erythronium,” Veratrum): it has lived on 
part of its food capital in order to place the rest in safety. But 
as a rule one, or even two, green leaves are sent up soon after 
germination, and then the contents of the storehouse are replen- 
ished by the activity of the assimilating surface. — 
The formation of assimilating organs in the seedling of a 
Seophilous plant is, however, very greatly limited by the short- 
ness of the growing season and the necessary formation of sane 
terranean organs. Here lies the explanation we were seeking ; 
the reduction of the cotyledons and the formation of a tuber are 
both adaptations to the geophilous habit. 
Suppose a race of primitive angiosperms to be specialized as 
*° RIMBACH, Ber. Deutsch. Bot. Gesell. 15:—. 1897. 
* IRMISCH, Beitr. z. vergleichenden Morphologie der Pflanzen. Halle. sha 
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