ASSIMILATION AND METASTASIS. 
which serve to protect the new bulb; the inflorescence subsequently dies down. The 
reserve-materials which accumulate in the daughter-bulbs are partly derived from those 
of the mother-bulb ; but are completed by the products of assimilation of the green 
leaves of the flower-stalk. When the flower-stalk has also died down, nothing remains 
of the whole plant but the bud which has developed into a new bulb. For a time it 
does not put out any new organs, but is apparently dormant ; but in the interior the 
end of the stem continues to grow slowly, and produces new rudiments of leaves and the 
flower-bud for the next year ; when the process now described is repeated. 
So far we have only pointed out the rela- 
tion of the starch and of the sugar produced 
from it to the growth of the plant ; there are 
formed however along with it, and probably 
likewise at the expense of these carbo-hydrates, 
other substances, such as the colouring matter 
of flowers, the oil in the pollen-grains, &c. 
The albuminoids at first contained in the bulb- 
scales become transported to a distance from 
them, and furnish the material for the forma- 
tion of the protoplasm in the young cells of 
the growing flower-stalk ; a large part is evi- 
dently employed in producing the chlorophyll- 
granules in the foliage-leaves as they become 
green. Their function is now to produce at 
least as much formative material by assimila- 
tion as is required to build up the transitory 
inflorescence and to supply the bulb. 
2. The ripe seed of Ricinus communis con- 
tains a very small embryo in the middle of 
a very large endosperm ; neither contains 
starch, sugar, nor any other carbo-hydrate, 
if we exclude the very small amount in weight 
of the cellulose of the thin cell-walls. The 
reserve food-material consists of a great quan- 
tity of oil (as much as 60 per cent.) and albu- 
minoids, the admixture and composition of 
which have already been described on p. 53. 
The very small quantity of these substances 
contained in the embryo would only suffice 
for the first and very inconsiderable develop- 
ment of the seedling; its enormous increase 
in size during germination must therefore 
be attributed almost entirely to the sub- 
stances deposited in the endosperm. The 
endosperm of Ricinus enlarges very consider- 
ably, as Mohl first showed, during germina- 
tion, and the material required for its growth 
must therefore be diverted from the embryo, 
in the endosperm, with their surfaces in contact with one another, long after the 
root and the hypocotyledonary part of the stem have emerged from the seed ; they 
are in contact by their backs with the tissue of the endosperm which surrounds 
them on all sides, and absorb the reserve-materials from it, while they keep pace 
slowly with its enlargement. When the parts of the seedling have increased very 
considerably and the root has developed a number of lateral roots, the hypocoty- 
ledonary portion of the stem elongates so that the cotyledons are drawn out of the 
Fig. 470.— Longitudinal section through a germinating 
bulb of Ticlipa pracox: h the brown enveloping membrane, 
k the flattened stem which forms the base of the bulb and 
bears the bulb-scales j/z ; si the elongated part of the stein 
which bears the foliage-leaves I' ., and terminates in the 
flower ; c the ovary, / perianth, a anthers ; 2 a lateral bulb 
in the axil of the youngest bud-scale, which developes into 
tlie bud of next year's bulb ; iv the roots which spring from 
the fibro-vascular bundles of the base of the bulb. 
The two thin broad cotyledons remain 
