Personality of plants

SCIENCE IN THE PLANT WORLD
on his return the next morning. It took several
nocturnal visits to unravel the mystery and
discover that the flowers folded themselves
and retired so adroitly into the surrounding
foliage each evening that they were completely
hidden.
The Acacia is a plant which closes up at
night; the same phenomenon is very striking
in the Oxalis. The common Bean sleeps stand-
ing: that is, its leaves close upward instead of
downward. The little blue Veronica flower,
so strikingly brilliant and attractive in the day-
time, tucks itself in so snugly at bedtime that
it becomes quite inconspicous. A Marigold
called Calendula Pluvialis even contracts its
corolla every time the sun is veiled by a pas-
sing cloud. These sleep movements all have
a scientific purpose. Their main object, just
as in animals, is to reduce bodily activities to
a low ebb and so to give the plant a chance to
recuperate for another day's efforts. The con-
traction of all surfaces cuts down the radiation
of heat and moisture and presents less resis-
tance to outside elements. The plant is in a
quiescent, somnolent state.
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