simply from irritation, because cold and darkness are negative quantities,
and on that account sensation or volition are implied, and in consequence a
sensorium or union of their nerves. So when we go into the light, we
contract the iris; not from any stimulus of the light on the fine muscles
of the iris, but from its motions being associated with the sensation of
too much light on the retina: which could not take place without a
sensorium or center of union of the nerves of the iris with those of
vision. See Botanic Garden, Part I. Canto 3. l. 440. note.

Besides these organs of sense, which distinguish cold, moisture, and
darkness, the leaves of mimosa, and of dionæa, and of drosera, and the
stamens of many flowers, as of the berbery, and the numerous class of
syngenesia, are sensible to mechanic impact, that is, they possess a sense
of touch, as well as a common sensorium; by the medium of which their
muscles are excited into action. Lastly, in many flowers the anthers, when
mature, approach the stigma, in others the female organ approaches to the
male. In a plant of collinsonia, a branch of which is now before me, the
two yellow stamens are about three eights of an inch high, and diverge from
each other, at an angle of about fifteen degrees, the purple style is half
an inch high, and in some flowers is now applied to the stamen on the right
hand, and in others to that of the left; and will, I suppose, change place
to-morrow in those, where the anthers have not yet effused their powder.

I ask, by what means are the anthers in many flowers, and stigmas in other
flowers, directed to find their paramours? How do either of them know, that
the other exists in their vicinity? Is this curious kind of storge produced
by mechanic attraction, or by the sensation of love? The latter opinion is
supported by the strongest analogy, because a reproduction of the species
is the consequence; and then another organ of sense must be wanted to
direct these vegetable amourettes to find each other, one probably