122 THE RANGE OF THE PRIMROSE
thinks it is to be accounted for by the presence or absence of a
moth which visits alike the primrose and the cowslip. Whether or
no there has been a troublesome moth at work in the area of the
Bardfield Oxlip I am afraid it would be useless to enquire. It does
not seem possible that insects could hybridise and annihilate a
species ; yet what other solution is forthcoming ?
The broad teaching of Darwin's book is that hybridisation in
these members of the genus Primula is sometimes common, and
that the conditions under which this takes place in nature are not
often known. The organs of reproduction in forms recently dif-
ferentiated appear, in our ignorance, to act capriciously.
Whatever may have been the cause, the fact of the local extinc-
tion of the primrose dates from a time long past, for there are large
areas now destitute of both species. A melancholy interest lies in
defining these areas, and more particularly in marking the boundary
of P. elatior and watching its gradual extinction. Its original
boundary perhaps extended beyond the limit now marked by the
absence of the primrose. It still extends far into Suffolk and into
Cambridgeshire, but is otherwise unknown in the British Isles.
A more satisfactory task is that of watching its behaviour both in
a wild state and under cultivation, and comparing its changes with
those of nearly allied species. The changes those species undergo
may be roughly tabulated as follows :—
Primrose. P. vulgaris.
In a wild state.—Pedicels vary in length ; blooms change slightly in
colour ; corolla (rarely) becomes foliaceous.
Under cultivation.—In addition to the above changes floral enve-
lopes increase in number, and flower eventually becomes
double, or produces "hose-in-hose." Blooms vary greatly in
colour.
Cowslip. P. veris.
In a wild state.—Scape and pedicels vary in their respective lengths,
and blooms vary in size to such a degree that the plant simulates,
and is often mistaken for, the oxlip.
Under cultivation.—In addition to the above changes flowers alter
greatly in colour and finally produce the polyanthus.
Common Oxlip (a hybrid between P. veris and P. vulgaris.)
Under cultivation.—Plants become robust and corolla sometimes
changes in colour.