One who is unfamiliar with the remarkable doings of blossoms in
association with their insect honey-sippers might consider it somewhat
surprising to attribute "manners" to a flower. But who that has seen
the sage-blossom clap its bee visitor on the back as she ushers him in
at the threshold of her purple door, marking him for her own with her
dab of yellow pollen as she almost pushes him into the nectar feast
within; who that has witnessed the almost roguish demonstration which
the tiny andromeda-bell extends to the sipping bee at its doorway--who
that has seen these can any longer doubt that blossoms have "manners"
as well as we bigger, more conscious beings? Yes, manners,
unquestionably--"bad manners," it would almost seem, in some
instances, as, for example, in this andromeda blossom-bell, which, in
its perfume and its nectar, deliberately invites the tiny _Andrena_
bee, only to deluge its little, black, hairy face with a smothering
shower of dusty pollen. A remarkable style of etiquette, surely, that
is, from our _human_ standpoint. But in the realm of Flora the
standards of decorum, so far as greeting is concerned, are not
governed by artificial whim. There is no "smart set" to dictate and
set the fashion for others less smart to follow. Each individual
flower is a law unto itself as to the method of its greeting to its
especial insect friend. The blossom etiquette of welcome is literally
as "old as the hills," and has come down with little change from an
ancestry which dates back perhaps to a period when there were no human
"ancestors" on the globe. So these "manners" are natural and original,
to say the least, even if they are so queer sometimes. What would you
think of a friend whose hospitable smile and welcome at his doorway
should invite you thither only that your foot might touch a trigger
and let fall the floor beneath you, while at the same time you are
half suffocated with an explosion of a bushel of yellow corn meal? Yet
such is something like the spectacular reception which the lotus
clover, the desmodium, and the genista flowers consider the most
expressive form of welcome. But the little bees seem to enjoy it, and
go again and again to each successive flower, well knowing what the
result will be, and apparently "touching off the trigger" without a
tremor, or even holding their breath. But they and their foreparents
for thousands of years have got accustomed to it, and I half imagine
that the baby bee, even in his first visit to one of these blossoms,
knows precisely what will happen. Pop! pop! go the exploding flowers,
one after the other, at each touch of the bee, throwing up a cloud of
yellow pollen which covers the bodies of the insects until they are as
dusty as little millers.
There is an endless variety in these various welcomes among the
flowers, and our barberry has one of the queerest of them all. Poets
of all ages have loved to dwell upon the flowers--their "swete smels,"
exquisite forms, fragrance, and colors. The droning bees in an
environment of fragrant bloom have moved many a poetic pen to
inspiration. But it is not often that the bards have seen deep enough
into the floral mysteries to immortalize the _doings_ of the blossoms.
I recall one such allusion, however, with reference to this
mischievous blossom of the barberry. How well old Hosea Biglow knew
its pranks!
"All down the loose-walled lanes in archin' bowers
The barb'ry droops its strings o' golden flowers,
Whose shrinkin' hearts the school-gals love to try
With _pins_. They'll worry yourn so, boys, bime-by."
Those "shrinkin' hearts" of the barberry blossom, so long the wonder
and amusement of children, including many children of adult growth,
have, so far as I know, herein found their first and only
historian--historian, but not interpreter. For Hosea Biglow, nor his
literary parent, James Russell Lowell, never dreamed of the
significance of this strange spectacle in the shrinkin' hearts of the
barberry bloom when surprised with the point of a pin.
But the bee can tell us all about it. He has known this singular trick
in the barberry for ages, and kept the secret all to himself. Only
comparatively recently (1859 or thereabouts) did the secret leak out,
when Darwin, by the previous hints of several other philosophers,
discovered the key which unlocked the mystery of this as well as
thousands of other similar riddles among the flowers.
These strange "manners" of the blossoms had then a deep vital
principle at their base. They had not _always_ been thus, but had
gradually, through long ages of time, changed and modified their
shapes, colors, odors, nectar, and their manners for one purpose--_to
insure_ their pollen being conveyed away upon the bodies of insects
and carried to a _second_ flower, and there placed upon the stigma to
insure fertilization and development of the seed.
[Illustration: "In archin' bowers"]
The plans, devices, tricks, and pranks by which flowers accomplish
this result are past belief. I have indicated only a few by way of a
hint, and in previous papers on the bluebottle and figwort have
described others, but none quite similar to the barberry.
[Illustration: Fig. 1]
We all know the barberry, the prickly, thorny barberry, whether with
its "strings o' golden flowers" or its drooping clusters of brilliant
scarlet acid berries. But each one of those berries is but a token of
a bee's visit, as we shall presently see. At Fig. 1 I have shown a
plan of the barberry blossom seen from below, its yellow sepals and
petals open, and opposite each of the inner set, and pressed against
it, a stamen. This stamen is shown below in three stages--closed,
partly open, and fully open--the queer little ear-shaped lids finally
drawn up, showing the pollen-pockets, and also withdrawing a portion
of the pollen from the cavity. At the centre is seen the circular tip
of the ovary which finally becomes the berry--that is, when the little
scheme here planned has been fulfilled. This circular form represents
the tip of the ovary, and the little toothed rim the _stigma_. Now
what is the intention here expressed? This construction represents a
plan, first, to invite a bee--this is done by its color, its
fragrance, and its nectar, which is secreted in a gland at the base of
each petal, near the centre of the flower; secondly, to make that bee
bear away the pollen; thirdly, to cause that same bee to place this
pollen on the stigma rim of the next flower he visits. In Fig. 2 we
see how beautifully this plan is carried out by the insect, without
his suspecting how perfectly he has been utilized. At A we see the
same flower cut open sideways, the waiting, expectant stamens tucked
away at the sides, leaving a free opening to the base of the flower.
Now comes our bee. He must needs hang back downward to sip at the
drooping flower. As his tongue enters, and finally touches the base of
these stamens, _clap_! they come one after another against his tongue
and face, and there deposit their load of pollen (B). The bee, who has
doubtless got over his surprise at this demonstration--if, indeed, he
ever had any--now flies to another blossom, perhaps on the same
cluster (C). Entering it as before, the notched edge of the stigmatic
rim comes in contact with the pollen on his tongue and face,
and the flower is thus fertilized by pollen from another barberry
blossom, the intention of the flower now perfectly realized in
_cross_-fertilization.
[Illustration: Fig. 2]
The seeds from _cross_-fertilized flowers are almost invariably more
vigorous, and thus yield more vigorous plants, than those of flowers
fertilized with their own _pollen_, and this is why most flowers have
necessarily developed some means by which cross-fertilization can be
secured. And this has been done through evolution working on the lines
of _natural_ selection, those seedlings which had originally happened,
by a variation in the flower, to be thus favored by some chance
peculiarity which insured cross-fertilization, winning in the struggle
with the previous weaker individuals, and finally supplanting them
altogether.