yielded seeds. Flowers which are self-fertile
would naturally produce seeds under these circumstances;
but I am greatly surprised that Delphinium consolida,
as well as another species of Delphinium, and Viola
tricolor, should have produced a fair supply of seeds
when thus treated; but it does not appear that he compared
the number of the seeds thus produced with those yielded
by unmutilated flowers left to the free access of
insects: ‘Bedeutung der Nektarien’
1833 pages 123-135.) On the other hand, in some large
masses of Geranium phaeum which had escaped out of
a garden, I observed the unusual fact of the flowers
continuing to secrete an abundance of nectar after
all the petals had fallen off; and the flowers in
this state were still visited by humble-bees.
But the bees might have learnt that these flowers with
all their petals lost were still worth visiting, by
finding nectar in those with only one or two lost.
The colour alone of the corolla serves as an approximate
guide: thus I watched for some time humble-bees
which were visiting exclusively plants of the white-flowered
Spiranthes autumnalis, growing on short turf at a
considerable distance apart; and these bees often
flew within a few inches of several other plants with
white flowers, and then without further examination
passed onwards in search of the Spiranthes. Again,
many hive-bees which confined their visits to the
common ling (Calluna vulgaris), repeatedly flew towards
Erica tetralix, evidently attracted by the nearly similar
tint of their flowers, and then instantly passed on
in search of the Calluna.
That the colour of the flower is not the sole guide,
is clearly shown by the six cases above given of bees
which repeatedly passed in a direct line from one
variety to another of the same species, although they
bore very differently coloured flowers. I observed
also bees flying in a straight line from one clump
of a yellow-flowered Oenothera to every other clump
of the same plant in the garden, without turning an
inch from their course to plants of Eschscholtzia
and others with yellow flowers which lay only a foot
or two on either side. In these cases the bees
knew the position of each plant in the garden perfectly
well, as we may infer by the directness of their flight;
so that they were guided by experience and memory.
But how did they discover at first that the above
varieties with differently coloured flowers belonged
to the same species? Improbable as it may appear,
they seem, at least sometimes, to recognise plants
even from a distance by their general aspect, in the
same manner as we should do. On three occasions
I observed humble-bees flying in a perfectly straight
line from a tall larkspur (Delphinium) which was in
full flower to another plant of the same species at
the distance of fifteen yards which had not as yet
a single flower open, and on which the buds showed
only a faint tinge of blue. Here neither odour
nor the memory of former visits could have come into