_Geranium maculatum_
_Flowers_--Pale magenta, purplish pink, or lavender, regular, 1 to 1-1/2
in. broad, solitary or a pair, borne on elongated peduncles, generally
with pair of leaves at their base. Calyx of 5 lapping, pointed sepals; 5
petals, woolly at base; 10 stamens; 1 pistil with 5 styles. _Fruit:_ A
slender capsule pointed like a crane’s bill. In maturity it ejects seeds
elastically far from the parent plant. _Stem:_ 1 to 2 ft. high, hairy,
slender, simple or branching above. _Leaves:_ Older ones sometimes
spotted with white; basal ones 3 to 6 in. wide, 3 to 5 parted, variously
cleft and toothed; 2 stem leaves opposite.
_Preferred Habitat_--Open woods, thickets, and shady roadsides.
_Flowering Season_--April-July.
_Distribution_--Newfoundland to Georgia, and westward a thousand miles.
Sprengel, who was the first to exalt flowers above the level of mere
botanical specimens, had his attention led to the intimate relationship
existing between plants and insects by studying out the meaning of the
hairy corolla of the common Wild Geranium of Germany _(G. sylvaticum)_,
being convinced, as he wrote in 1787, that “the wise Author of Nature
has not made even a single hair without a definite design.” A hundred
years before, Nehemias Grew had said that it was necessary for pollen to
reach the stigma of a flower in order that it might set fertile seed;
and Linnaeus had to come to his aid with conclusive evidence to convince
a doubting world that this was true. Sprengel made the next step
forward, but his writings lay neglected over seventy years because he
advanced the then incredible and only partially true statement that a
flower is fertilized by insects which carry its pollen from its anthers
to its stigma. In spite of his discoveries that the hairs inside the
geranium’s corolla protect its nectar from rain for the insect’s
benefit, just as eyebrows keep perspiration from falling into the eye;
that most flowers which secrete nectar have what he termed “honey
guides”--spots of bright color, heavy veining, or some such pathfinder
on the petals--in spite of the most patient and scientific research that
shed great light on natural selection a half-century before Darwin
advanced the theory, he left it for the author of “The Origin of
Species” to show that cross-fertilization--the transfer of pollen from
one blossom to another, not from anthers to stigma of the same
flower--is the great end to which so much marvellous mechanism is
chiefly adapted. Cross-fertilized blossoms defeat self-fertilized
flowers in the struggle for existence.
No wonder Sprengel’s theory was disproved by his scornful contemporaries
in the very case of his Wild Geranium, which sheds its pollen before it
has developed a stigma to receive any; therefore no insect that had not
brought pollen from an earlier bloom could possibly fertilize this
flower. How amazing that he did not see this! Our common wild
crane’s-bill, which also has lost the power to fertilize itself, not
only ripens first the outer, then the inner, row of anthers, but
actually drops them off after their pollen has been removed, to overcome
the barest chance of self-fertilization as the stigmas become receptive.
This is the geranium’s and many other flowers’ method to compel
cross-fertilization by insects. In cold, stormy, cloudy weather a
geranium blossom may remain in the male stage several days before
becoming female; while on a warm, sunny day, when plenty of insects are
flying, the change sometimes takes place in a few hours. Among others,
the common sulphur or puddle butterfly, that sits in swarms on muddy
roads and makes the clover fields gay with its bright little wings,
pilfers nectar from the geranium without bringing its long tongue in
contact with the pollen. Neither do the smaller bees and flies which
alight on the petals necessarily come in contact with the anthers and
stigmas. Doubtless the larger bees are the flowers’ true benefactors.
The so-called geraniums in cultivation are pelargoniums, strictly
speaking.