142 THE FLOWERING PLANT. 
fruit, as in dandelion, “thistledown,” &c. The dandelion is of 
further interest because the peduncle, which during ripening is 
directed along the ground, raises itself so that the fruits can 
readily blow away. The perianth of cotton-grass (really a sedge) 
consists of bristles which grow out into long hairs; a crown of 
hairs is found on the seeds of willow-herb, while a more general 
covering of hairs is present on willow and cotton seeds. ‘The seed 
of crane’s-bill, a near relative of the geranium, possesses a long 
feathery awn adapted for catching the wind. The base of the 
awn is also twisted, and this part when moist tends to screw the 
pointed seed into the ground. 
Many fruits or seeds, especially those of trees, are provided 
with an expanded ‘“ wing,” of various nature. In dime the stem 
of a flower cluster is provided with a large adherent bract, and 
in hornbeam the single fruit is in the axil of a trilobed bract. 
The fruits of maple, sycamore (fig. 58), berch, ash, and elm are 
themselves winged, and there is a membranous margin in those 
of dock and parsnip. Scotch fir presents an example of winged 
seeds. 
(4.) Animals help to distribute seeds and fruits in a variety of 
ways. Many fruits are provided with hooks, and some with 
sticky hairs, by which they become attached to the coats of 
animals. Such cases are found among plants low in stature, 
where alone they would be useful. The calyx of forget-me-not 
and fruits of burdock and cleaver are common British examples. 
In plumbago the calyx with its viscid glandular hairs (p. 112) 
persists and answers the same purpose. 
Succulent fruits appear to be especially adapted by their colour, 
scent, and edibility to attract animals, particularly birds. The 
well-protected seeds they contain are able to resist digestion, and 
are, doubtless, frequently transported to considerable distances. 
Small portions of earth containing seeds must also frequently 
became attached to various animals. 
Germination.—This simply means the development of a seed 
into a young plant up to a period when it is able to obtain food 
from the exterior. The embryo contained in a seed is in a 
dormant state, and if the conditions are unfavourable, may so 
remain for a considerable length of time. A seed when kept 
damp and exposed to the air will germinate if the temperature is 
suitable (say about 35° centigrade). Take, for example, an ex- 
albuminous seed, like that of bean. The contained embryo first 
swells and bursts the seed-coat. The radicle elongates, and then 
the plumule, at first strongly curved, raises itself from between 
the cotyledons and rapidly grows. The cotyledons remain within 
the seed-coat, and here simply serve as stores of reserve materials, 
