(Ipomoea pandurata) Morning-glory family
Flowers - Funnel form, wide-spread, 2 to 3 in. long, pure white
or pinkish purple inside the throat; the peduncles 1 to 5
flowered. Stem: Trailing over the ground or weakly twining, 2 to
12 ft. long. Leaves: Heart,
fiddle, or halbert shaped (rarely
3-lobed), on slender petioles. Root: Enormous, fleshy.
Preferred Habitat - Dry soil, sandy or gravelly fields or hills.
Flowering Season - May-September.
Distribution - Ontario, Michigan, and Texas, east to the Atlantic
Ocean.
No one need be told that this flaring, trumpet-shaped flower is
next of kin to the morning-glory that clambers over the trellises
of countless kitchen porches, and escapes back to Nature's garden
whenever it can. When the ancestors of these blossoms welded
their five petals into a solid deep bell, which still shows on
its edges the trace of five once separate parts, they did much to
protect their precious contents from rain; but some additional
protection was surely needed against the little interlopers not
adapted to fertilize the flower, which could so easily crawl down
its tube. Doubtless the hairs on the base of the filaments,
between which certain bumblebees and other long-tongued
benefactors can easily penetrate to suck the nectar secreted in a
fleshy disk below, act as a stockade to little would-be
pilferers. The color in the throat serves as a pathfinder to the
deep-hidden sweets. How pleasant the way is made for such insects
as a flower must needs encourage! For these the perennial wild
potato vine keeps open house far later in the day than its annual
relatives. Professor Robertson says it is dependent mainly upon
two bees, Entechnia taurea and Xenoglossa ipomoeae, the latter
its namesake.
One has to dig deep to find the huge, fleshy, potato-like root
from which the vine derived its name of man-of-the-earth. Such a
storehouse of juices is surely necessary in the dry soil where
the wild potato lives.
Happily, the COMMON MORNING-GLORY (I. purpurea) - the
Convolvulus major of seedsmen's catalogues - has so commonly
escaped from cultivation in the eastern half of the United States
and Canada as now to deserve counting among our wild flowers,
albeit South America is its true home. Surely no description of
this commonest of all garden climbers is needed; everyone has an
opportunity to watch how the bees cross-fertilize it.
The vine has a special interest because of Darwin's illuminating
experiments upon it when he planted six self-fertilized seeds and
six seeds fertilized with the pollen brought from flowers on a
different vine, on opposite sides of the same pot. Vines produced
by the former reached an average height of five feet four inches,
whereas the cross-pollenized seed sent its stems up two feet
higher, and produced very many more flowers. If so marked a
benefit from imported pollen may be observed in a single
generation, is it any wonder that ambitious plants employ every
sort of ingenious device to compel insects to bring them pollen
from distant flowers of the same species? How punctually the
MOON-FLOWER (I. grandiflora), next of kin to the morning-glory,
opens its immense, pure white, sweet-scented flowers at night to
attract night-flying moths, because their long tongues, which
only can drain the nectar, may not be withdrawn until they are
dusted with vitalizing powder for export to some waiting sister.
GRONOVIUS' or COMMON DODDER; STRANGLE-WEED; LOVE VINE; ANGEL'S
HAIR
(Cuscuta gronovii) Dodder family
Flowers - Dull white, minute, numerous, in dense clusters. Calyx
inferior, greenish white, 5-parted; corolla bell-shaped, the 5
lobes spreading, 5 fringed scales within; 5 stamens, each
inserted on corolla throat above a scale; 2 slender styles. Stem:
Bright orange yellow, thread-like, twining high, leafless.
Preferred Habitat - Moist soil, meadows, ditches, beside streams.
Flowering Season - July-September.
Distribution - Nova Scotia and Manitoba, south to the Gulf
States.
Like tangled yellow yarn wound spirally about the herbage and
shrubbery in moist thickets, the dodder grows, its beautiful
bright threads plentifully studded with small flowers tightly
bunched. Try to loosen its hold on the support it is climbing up,
and the secret of its guilt is out at once; for no honest vine is
this, but a parasite, a degenerate of the lowest type, with
numerous sharp suckers (haustoria) penetrating the bark of its
victim, and spreading in the softer tissues beneath to steal all
their nourishment. So firmly are these suckers attached, that the
golden thread-like stem will break before they can be torn from
their hold.
Not a leaf now remains on the vine to tell of virtue in its
remote ancestors; the absence of green matter (chlorophyll)
testifies to dishonest methods of gaining a living (see Indian
pipe); not even a root is left after the seedling is old enough
to twine about its hard-working, respectable neighbors. Starting
out in life with apparently the best intentions, suddenly the
tender young twiner develops an appetite for strong drink and
murder combined, such as would terrify any budding criminal in
Five Points or Seven Dials! No sooner has it laid hold of its
victim and tapped it, than the now useless root and lower portion
wither away, leaving the dodder in mid-air, without any
connection with the soil below, but abundantly nourished with
juices already stored up, and even assimilated, at its host's
expense. By rapidly lengthening the cells on the outer side of
its stem more than on the inner side, the former becomes convex,
the latter concave; that is to say, a section of spiral is formed
by the new shoot, which, twining upward, devitalizes its
benefactor as it goes. Abundant, globular seed vessels, which
develop rapidly, while the blossoming continues unabated, soon
sink into the soft soil to begin their piratical careers close
beside the criminals which bore them; or better still, from their
point of view, float downstream to found new colonies afar. When
the beautiful jewelweed - a conspicuous sufferer - is hung about
with dodder, one must be grateful for at least such symphony of
yellows.
Previous: INDIAN HEMP: AMYROOT
Next: VIRGINIA WATERLEAF
|
|
SHARE | |
ADD TO EBOOK |