152 Sargant , — The Reconstruction of a Race of 
known of the conditions under which the seeds of Sparganium , Juncus , and 
Ltizula germinate, and therefore no precise estimate can be given of the 
extent to which they might affect the structure of the embryo. All that 
can be said is that considerable reduction of structure commonly occurs in 
the embryo and seedling of aquatic and semi-aquatic plants. 
The stem-axis of bulbous Monocotyledons is often all but suppressed 
in the embryo and seedling. Fleischer figures and describes the embryo 
of Leucojum aestivum. When two leaves are present within the cotyledonary 
sheath, the stem-apex which was between them is represented only by 
a limited region of actual cell-division. My own preparations furnish many 
instances of extreme suppression of the stem in the seedlings of leafy 
bulbs — Allium , Fritillaria , Galtonia , for example. In such seedlings the 
stem is often more reduced as compared with the leaves than it is in the 
mature plant. 
The fact that reduction has proceeded further in the seedling than in 
the mature plant admits of two explanations. It may be said that the 
absence of stem is a primitive feature, and therefore better marked in 
the young plant, according to the law of recapitulation. If this were the 
true explanation we should expect reduction of this sort to be most marked 
in species which on other grounds appear primitive. But this is not so. 
It is most clearly seen in aquatic forms and in Alpine or bulbous forms — 
all highly specialized types. 
If this explanation be rejected, the alternative is to suppose that in 
these exceptional forms the causes which result in suppression of the stem- 
axis operate more powerfully on the seedling than on the mature plant. 
In many of the instances quoted, this can be shown to be true. The seeds 
of aquatics, for example, commonly germinate under water, and thus the 
seedling is completely submerged, to begin with. It leads a more completely 
aquatic life in many cases than the adult plant which is only partially 
.submerged ( Sparganium ). Extreme reduction in all non-essential parts is 
essential in the seedling of Pistia , which has to become light enough to float 
up to the surface. 
The reduction of the seedling in Alpine and bulbous plants is due to 
other causes. For a full discussion of these I must refer to previous papers 
(Sargant, 72 , pp. 78-81, and 73, pp. 334-5). The essential point is that 
a seedling germinating in the short summer of an Alpine summit is faced 
with a task almost beyond its powers. If it is to survive the coming winter, 
the seedling must be safely buried in the ground by the end of the summer, 
and be provided also with a reserve-fund of food. The stem of such 
a seedling is commonly developed as a tuber in which food is stored. It 
rarely develops internodes in the first years of its life. Bulbous plants bear 
traces of evolution under conditions equally stringent, though many of them 
have to resist hot drought rather than cold in the dead season. 
