Primrose and Pimpernel 221 
style they have to penetrate, those of the short-styled 
form being much larger than those of the other form. 
By these peculiarities in-breeding among Primroses 
is effectually prevented, for the plant that produces 
long-styled flowers does not present us with a single 
short-styled blossom, nor does the plant with the 
short-styled produce a single long-styled flower. 
There are no less than five native species of Primula: 
the Primrose, the Oxlip, the Cowslip, the Bird’s-eye, 
and the Scottish Primrose. With the exception of 
the last-named, all these agree in having the long- and 
short- styled flowers—or, as modern botanists say, they 
are dimorphic—and it therefore seems probable that 
the ancestral form from which these existing species 
-were evolved had become dimorphic before these 
branched off. . 
These plants all have the flowers grouped in an 
umbel which is borne on a tall leafless stalk, with 
the apparent exception of the Common Primrose, 
which, everybody knows, produces a cluster of flowers, 
each on a long slender foot-stalk from the heart 
of the leaf-rosette. But a vertical section through 
the entire plant would show that even the Primrose 
flowers are arranged like those of its congeners, only 
the common stalk is so stunted, or suppressed, that 
the flowers appear to spring singly from the rootstock 
direct. Sometimes, however, the Primrose resolves 
to let us see the true nature of its flower-grouping, 
and it develops the common stalk, so that it closely 
resembles the Oxlip (Primula elatior). 
The Cowslip (P. veris) has deeper yellow flowers, 
of smaller size, and with less inflated calyx; and all 
three of these have wrinkled leaves. The Bird’s-eye 
