78 MR. C. DARWIN ON THE DIMORPHIC CONDITION 
will designate the two forms as long-styled and short-styled. Those 
botanists with whom I have spoken on the subject have looked at 
the case as one of mere variability, which is far from the truth. 
In the Cowslip, in the long-styled form, the stigma projects just 
above the tube of the corolla, and is externally visible; it stands 
high above the anthers, which are situated halfway down the tube, 
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SP a P 
Long-styled. Short-styled. 
and cannot be easily seen. In the short-styled form the anthers 
are attached at the mouth of the tube, and therefore stand high 
above the stigma ; for the pistil is short, not rising above halfway 
up the tubular corolla. The corolla itself is of a different shape in 
the two forms, the throat or expanded portion above the attach- 
ment of the anthers being much longer in the long-styled than in 
the short-styled form. Village children notice this difference, as 
they can best make necklaces by threading and slipping the corollas 
of the long-styled flowers into each other. But there are much 
more important differences. The stigma in the long-styled plants 
is globular, in the short-styled it is depressed on the summit, so 
that the longitudinal axis of the former is sometimes nearly double 
that of the latter. The shape, however, is in some degree variable ; 
but one difference is persistent, namely, that the stigma of the 
long-styled is much rougher: in some specimens carefully com- 
pared, the papillze which render the stigmas rough were in the long- 
styled form from twice to thrice as long as in the short-styled. 
There is another and more remarkable difference, namely, in the 
size of the pollen-grains. I measured with the micrometer many 
