e, as in the rye, the pollen is protected until the
actual moment when it starts on its voyage through the air.

Another of the Nettle tribe, _Pilea serpyllifolia_--a plant often
cultivated in our greenhouses--is also explosive, and its little puffs of
smoke-like pollen have gained for it the popular name of the artillery
plant. Its power of explosion must be of value to it as counterbalancing
the disadvantage, to a wind-fertilised plant, of such a lowly habit.

The adaptations found in the female organs are chiefly such as increase
the surface capable of receiving the pollen, and therefore increase the
chance of fertilisation. A big stigmatic surface is common: not only is
the receptive part of the style large, but it usually bears very large
stigmatic papillae, which gives a velvety hoary look to this type of
stigma. In the grasses the three divisions of the stigma are always more
or less conspicuous; and reach a climax, in this respect, in the huge
beard-like tangle of the maize.

Some of the most interesting cases of wind fertilisation are those in
which an isolated instance occurs in a Natural Order otherwise served by
insects. Thus in the Rosaceae, _Poterium sanguisorba_ is wind
fertilised, and has long pendent stamens, and a tufted stigma; while the
closely allied _Sanguisorba officinalis_, although it secretes nectar
(and this can only mean that it hopes to attract insects), retains the
tufted stigma of its anemophilous relatives.

In the case of the Kerguelen cabbage (_Pringlea antiscorbutica_), the
cause of its degeneration seems to be the want of winged insects on the
wind-blown shores on which it grows. It has acquired some anemophilous
characters--_e.g._, increased stigmatic surface and exserted anthers.
Its flowers are inconspicuous like those of wind-fertilised plants in
general, and it seems in fair way to lose its petals altogether--many
flowers only retaining a single one. The entomophilous ancestry of
Pringlea is clearly shown by the occasional remnants of coloured markings
in the petals, like those which in other flowers serve as finger-posts to
visiting-insects, and are called nectar-guides.

But these are digressions--sidepaths of tempting detail which have lured
me from the straight highway. However, they have brought me back to the
main road.

In Blomefield's _Observations in Natural History_ (p. 332), he points out
that "however much the seasons may differ in different years, the
ph