him against a Holly. Loki tipped an arrow with a piece of
Mistletoe, against which Balder was not proof, and gave it to Balder's
brother. This, unfortunately, pierced him to the heart, and he fell
dead. Some drops of his blood spurted on to the Holly, which accounts
for the redness of the berries; the Mistletoe was so grieved that she
has ever since borne fruit like tears; and the crow, whose form Loki had
taken, and which till then had been white, was turned black.

This pretty myth accounts for several things, but is open to fatal
objections.

Recent attempts to explain the facts of Nature are not less fascinating,
and, I think, more successful.

Why then this marvellous variety? this inexhaustible treasury of
beautiful forms? Does it result from some innate tendency in each
species? Is it intentionally designed to delight the eye of man? Or has
the form and size and texture some reference to the structure and
organisation, the habits and requirements of the whole plant?

I shall never forget hearing Darwin's paper on the structure of the
Cowslip and Primrose, after which even Sir Joseph Hooker compared
himself to Peter Bell, to whom

A primrose by a river's brim
A yellow primrose was to him,
And it was nothing more.

We all, I think, shared the same feeling, and found that the explanation
of the flower then given, and to which I shall refer again, invested it
with fresh interest and even with new beauty.

A regular flower, such, for instance, as a Geranium or a Pink, consists
of four or more whorls of leaves, more or less modified: the lowest
whorl is the Calyx, and the separate leaves of which it is composed,
which however are sometimes united into a tube, are called sepals; (2) a
second whorl, the corolla, consisting of coloured leaves called petals,
which, however, like those of the Calyx, are often united into a tube;
(3) of one or more stamens, consisting of a stalk or filament, and a
head or anther, in which the pollen is produced; and (4) a pistil, which
is situated in the centre of the flower, and at the base of which is the
Ovary, containing one or more seeds.

Almost all large flowers are brightly coloured, many produce honey, and
many are sweet-scented.

What, then, is the use and purpose of this complex organisation?

It is, I think, well established that the main object of the colour,
scent, and honey of flowers is to attract insects, which are of use to
the plant in carrying