Roses and Apples 51 
common with the Whitethorn or Hawthorn, previously 
referred to, the Blackthorn has learned this trick of 
protecting itself from being eaten up by cattle,—a 
stab by one of these thorns ou a sensitive muzzle 
being sufficient to discourage horse or ox. The white 
blossoms are small, but, appearing before the leaves 
have unrolled, are very conspicuous in contrast with 
the black branches. The calyx has five lobes, and 
the petals are five; the stamens are numerous, but 
there is only one carpel, terminating in a long style, 
and containing two seed-eggs, of which as a rule only 
one grows to be a proper seed. The flowers are 
honeyed, and the stigma is ripe for fertilisation before 
the pollen of that flower is shed,—in fact, before the 
flower is fully open,—but should no visiting insect 
bring pollen from farther along the hedgerow, crossing 
may be dispensed with. ‘The smaller bees (Andrena) 
and flies are the fertilising agents. As a result of 
fertilisation, the walls of the ovary swell and thicken 
with pulp as the carpel enlarges, and both calyx and 
corolla drop off; and five or six months later it has 
developed into a round black plum, 
thinly covered with a mealy wax 
(“bloom”), which gives it a bluish 
appearance. It is probable that this 
wax is secreted for the protection of 
the fruit until it is ripe, either in 
keeping off dampness or making the 
skin objectionable to insects that would 
otherwise attack it. From the Sloeg 
through its sub-species our cultivated — Chey Blossom 
plums have been evolved by artificial selection. 
Our Dwarf Cherry (P. cerasus) is something 
