Roses and Apples 43 
Though some of the Potentillas are tufted and even 
shrubby, most of the British species show a tendency 
to prostrate stems, some of them rooting at intervals. 
Eight of the native species have yellow flowers, two 
have become white and one purple; one species has 
a conspicuous enlarged and coloured receptacle. There 
you have in our paltry dozen of native species (out 
of one hundred and twenty known to inhabit the 
world) a sufficient number of tendencies to produce 
the Strawberry. 
Suppose that one like the Barren Strawberry 
with white flowers and trefoil leaves had acci- 
dentally varied in the direction of its receptacle 
growing large and spongy like the Marsh Cinquefoil, 
there would be a tendency in its offspring to repeat 
the—let us say—malformation. If its size and 
glowing colour attracted the birds that have a weak- 
ness for crimson or scarlet, and they ate its flesh with 
the attached nutlets, the contained seeds would pass 
through the bird’s digestive organs uninjured and be 
sown in richer soil. This would give the seedlings 
an advantage, and tend to fix the character by which 
they had benefited. Then, if the production of a 
sweet fluid (nectar) on the surface of the receptacle 
was extended to the interior of the spongy receptacle 
so that it grew sweet and juicy, this would no doubt 
cause the plant to be still more sought out by birds 
“with a sweet tooth,’ and the seeds to be more 
effectually distributed. We all know how plentiful 
the Wild Strawberry is, and how plastic it has proved 
in the hands of the fruit-grower, who has got from 
it a very large number of cultivated varieties differing 
in the size, colour, and peculiar flavours of the fruit. 
