1 1 2 
GERMINATION 
shoot. The cotyledons as a rule come up too, turn green, 
and act as the first foliage leaves, but if there is any endo- 
sperm they first of all absorb the reserves it contains. In a 
few exalbuminous seeds, e.g. pea, the cotyledons are so full 
of reserves that by the time they are exhausted the young 
plant is well enough grown to be independent, and there is 
no need for them to turn green, nor do they. Such also is 
the case in a few albuminous seeds, eg. the Gramineae. 
Observations made by Detmer 1 on the heights, weights, 
&c., of plants grown from heavy and light seeds show 
that, other things being equal, the former are as superior to 
the latter as the offspring of cross- to that of self-fertilisation, 
so that this is an important factor in the life-history. It 
might pay a plant to give up cross-fertilisation and expend 
the saving on heavier or more numerous seed. As usual, a 
balance must be struck between opposing necessities; the 
heavier the seed the less its chance of distribution. 
An interesting point seen in some seedlings is the tran- 
sitional stages towards the mature state (p. 29). Good 
examples are Acacia, Bossiaea, Ulex, Hakea, succulents, &c. 
Vegetative Reproduction. Frequently portions of 
the vegetative organs, specialised or not, are detached and 
grow into new plants. The detachment need not precede 
the growth of the new plant, but may follow it, as in the 
case of young strawberry-plants formed upon the runners. 
It is of interest to notice the ways in which the young 
daughter-plants are nourished. If the detached portion be 
not green, e.g. a potato tuber, reserve materials must be 
stored in it to start its growth and keep it growing until it 
can assimilate, so that it is the physiological though not the 
morphological equivalent of a seed (gardeners speak of 
‘ seed-potatoes ’). If the young plant, as in the strawberry, 
remain in connection with the parent, no reserves are needed, 
the parent feeding it till it is capable of independent growth. 
Vegetative reproduction is certain, effective, and econo- 
mical ; the profusion of such plants as daisies, buttercups, 
raspberries, hyacinths, is largely due to it. Its chief disad- 
vantage is the loss of the benefits of fertilisation. 
1 Detmer, Keimungsphysiologie ; Lubbock, Seedlings ; Goebel, 
Organography of Plants ; Vandevelde, De Kie?ning der Zaadplanten, 
in Bot. Jaarb., Gent, 1897 (literature list). 
