Ouar. IT. THE COMMON OXLIP. ically 2 |


hexeafter see good reason to believe. The case of
the oxlip is interesting; for hardly any other in-
stance is known of a hybrid spontaneously arising
in such large numbers over so wide an extent of coun-
try. The common oxlip (not the P. elatior of Jacq.)
is found almost everywhere throughout England, where
both cowslips and primroses grow. In some districts,
as I have seen near Hartfield in Sussex and in parts
of Surrey, specimens may be found on the borders of
almost every field and small wood. In other districts
the oxlip is comparatively rare: near my own resi-
dence I have found, during the last twenty-five years,
not more than five or six plants or groups of plants.
It is difficult to conjecture what is the cause of this
difference in their number. It is almost necessary
that a plant, or several plants belonging to the same
form, of one parent-species, should grow near the
opposite form of the other parent-species; and it is
further necessary: that both species should be fre-
quented by the same kind of insect, no doubt a moth.
The cause of the rare appearance of the oxlip in
certain districts may be the rarity of some moth,
which in other districts habitually visits both the
primrose and cowslip.
