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flowers at night to attract night-flying moths, because their long tongues, which only can drain the nectar, may not be withdrawn until they are dusted with vitalizing powder for export to some waiting sister.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'SHAIR
(Cuscuta gronovii) Dodder family Flowers - Dull white, minute, numerous, in dense clusters.Calyx inferior, greenish white, 5-parted; corolla bell-shaped, the 5lobes 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.
VIRGINIA WATERLEAF
(Hydrophyllum Virginicum) Waterleaf family Flowers - White or purplish tinged, in a single or forking cluster on a long peduncle.Calyx deeply 5-parted, the spreading segments very narrow, bristly hairy.Corolla erect, bell-shaped, deeply 5-lobed; 5 protruding stamens, with soft hairs about their middle; 2 styles united to almost the summit.Stem: Slender, rather weak, to 3 ft.long, leafy, sparingly branched, from a scaly rootstock.Leaves: Alternate, lower ones on long petioles, 6 to 10 in.long, pinnately divided into 5 to 7 oblong, sharply toothed, acute leaflets or segments; upper leaves similar, but smaller, and with fewer divisions.
Preferred Habitat - Rich, moist woods.
Flowering season - May-August.
Distribution - Quebec to South Carolina, west to Kansas and Washington.
So very many flowers especially adapted to the bumblebee are in bloom when the cymes of the waterleaf uncoil, like the borages, from their immature roll, that some special inducement to attract this benefactor were surely needed.In high altitudes the clusters became deeper hued; but much as the more specialized bees love color, food appeals to them far more.Accordingly the five lobes of each little flower stand erect to increase the difficulty a short-tongued insect would have to drain its precious stores; the stamens are provided with hairs for the same reason; and even the calyx is bristly, to discourage crawling ants, the worst pilferers out.By these precautions against theft, plenty of nectar remains for the large bees.To prevent self-fertilization, pollen is shed on visitors, which remove it from a newly opened flower before the stigmas become receptive to any; but in any case these are elevated in maturity above the anthers, well out of harm's way.
Early in spring the large lower leaves are calculated to hold the drip from the trees overhead, hence the plant's scientific and popular names.
JIMSONWEED; JAMESTOWN WEED; THORN APPLE; STRAMONIUM; DEVIL'STRUMPET
