These adaptations are most easily recognised in irregular flowers; but they are
present in regular flowers, of which those of Linum offer a good instance, as I
will now endeavour to show.
I have already alluded to the rotation of each separate stigma in the long-
styled form of Linum perenne. In both forms of the other heterostyled species
and in the homostyled species of Linum which I have seen, the stigmatic surfaces
face the centre of the flower, with the furrowed backs of the stigmas, to which
the styles are attached, facing outwards. This is the case with the stigmas of
the long-styled flowers of L. perenne whilst in bud. But by the time the flowers
have expanded, the five stigmas twist round so as to face the circumference,
owing to the torsion of that part of the style which lies beneath the stigma. I
should state that the five stigmas do not always turn round completely, two or
three sometimes facing only obliquely outwards. My observations were made during
October; and it is not improbable that earlier in the season the torsion would
have been more complete; for after two or three cold and wet days the movement
was very imperfectly performed. The flowers should be examined shortly after
their expansion, as their duration is brief; as soon as they begin to wither,
the styles become spirally twisted all together, the original position of the
parts being thus lost.
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