(5/4.
The flowers have been described by Delpino, and in an admirable manner
by Mr. Farrer in the 'Annals and Magazine of Natural History' volume 2
4th series October 1868 page 256. My son Francis has explained 'Nature'
January 8, 1874 page 189, the use of one peculiarity in their structure,
namely, a little vertical projection on the single free stamen near its
base, which seems placed as if to guard the entrance into the two
nectar-holes in the staminal sheath. He shows that this projection
prevents the bees reaching the nectar, unless they go to the left side
of the flower, and it is absolutely necessary for cross-fertilisation
that they should alight on the left wing-petal.) Several years ago I
covered some plants under a large net, and these produced on one
occasion about one-third, and on another occasion about one-eighth, of
the number of pods which the same number of uncovered plants growing
close alongside produced. (5/5. 'Gardeners' Chronicle' 1857 page 725 and
more especially ibid 1858 page 828. Also 'Annals and Magazine of Natural
History' 3rd series volume 2 1858 page 462.) This lessened fertility was
not caused by any injury from the net, as I moved the wing-petals of
several protected flowers, in the same manner as bees do, and these
produced remarkably fine pods. When the net was taken off, the flowers
were immediately visited by bees, and it was interesting to observe how
quickly the plants became covered with young pods.
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