Dr.Kerner thought the milky juice in milkweed plants, especially abundant in the uppermost leaves and stems, serves to protect the flowers from useless crawling pilferers.He once started a number of ants to climb up a milky stalk.When they neared the summit, he noticed that at each movement the terminal hooks of their feet cut through the tender epiderm, and from the little clefts the milky juice began to flow, bedraggling their feet and the hind part of their bodies."The ants were much impeded in their movements," he writes, "and in order to rid themselves of the annoyance, drew their feet through their mouths.Their movements however, which accompanied these efforts, simply resulted in making fresh fissures and fresh discharges of milky juice, so that the position of the ants became each moment worse and worse.
Many escaped by getting to the edge of a leaf and dropping to the ground.Others tried this method of escape too late, for the air soon hardened the milky juice into a tough brown substance, and after this, all the strugglings of the ants to free themselves from the viscid matter were in vain." Nature's methods of preserving a flower's nectar for the insects that are especially adapted to fertilize it, and of punishing all useless intruders, often shock us yet justice is ever stern, ever kind in the largest sense.
If the asclepias really do kill some insects with their juice, others doubtless owe their lives to it.Among the "protected"insects are the milkweed butterflies and their caterpillars, which are provided with secretions that are distasteful to birds and predaceous insects."These acrid secretions are probably due to the character of the plants upon which the caterpillars feed,"says Dr.Holland, in his beautiful and invaluable "Butterfly Book." "Enjoying on this account immunity from attack, they have all, in the process of time, been mimicked by species in other genera which have not the same immunity." "One cannot stay long around a patch of milkweeds without seeing the monarch butterfly.
(Anosia plexippus), that splendid, bright, reddish-brown winged fellow, the borders and veins broadly black, with two rows of white spots on the outer borders and two rows of pale spots across the tip of the fore wings.There is a black scent-pouch on the hind wings.The caterpillar, which is bright yellow or greenish yellow, banded with shining black, is furnished with black fleshy 'horns' fore and aft."Like the dandelion, thistle, and other triumphant strugglers for survival, the milkweed sends its offspring adrift on the winds to found fresh colonies afar.Children delight in making pompons for their hats by removing the silky seed-tufts from pods before they burst, and winding them, one by one, on slender stems with fine thread.Hung in the sunshine, how charmingly fluffy and soft they dry!
Among the comparatively few butterfly flowers - although, of course, other insects not adapted to them are visitors - is the PURPLE MILKWEED (A.purpurasceus), whose deep magenta umbels are so conspicuous through the summer months.Hummingbirds occasionally seek it too.From Eastern Massachusetts to Virginia, and westward to the Mississippi, or beyond, it is to be found in dry fields, woods, and thickets.
The SWAMP MILKWEED (A.incarnata), on the other hand, rears its intense purplish-red or pinkish hoods in wet places.Its leaves are lance-shaped or oblong-lanceolate, whereas the purple milkweed's leaves are oblong or ovate-oblong.This is a smooth plant; and a similar species once reckoned as a mere variety (A.
pulchra) is the HAIRY MILKWEED.It differs chiefly in having some hairs on the under side of its leaves, and a great many hairs on its stem.Both plants bear erect, rather slender, tapering pods.
The POKE or TALL MILKWEED (A.exaltata - A.phytolaecoides of Gray) may attain a height of six feet if the moist soil in which it grows be exactly to its liking.Drooping or spreading umbels of flowers whose corolla segments are pale purplish green, and whose crown is clear ivory white or pink, appear from June to August from Maine to Georgia and far westward.Sometimes the tapering oblong leaves may be nine inches long.The erect seedpods are drawn out to an unusually long point.
One may always distinguish the low-growing FOUR-LEAVED MILKWEED(A.quadrifolia) from its relatives of ranker growth by its general air of refinement, as well as by the two pairs of thin, tapering leaves that grow in an upright whorl near the middle of the slender stem.Usually there are no leaves on the lower part.
Small terminal umbels of delicate pink and white fragrant flowers, which appear from May till July, give place to very narrow pointed pods in late summer.From Maine to Ontario southward to North Carolina and Arkansas is its range, in woods and thickets chiefly.
HEDGE or GREAT BINDWEED; WILD MORNING-GLORY; RUTLAND BEAUTY;BELL-BIND; LADY'S NIGHTCAP
(Convolvulus sepium; Calystegia sepium of Gray) Morning-glory family Flowers - Light pink, with white stripes or all white, bell-shaped, about 2 in.long, twisted in the bud, solitary, on long peduncles from leaf axils.Calyx of 5 sepals, concealed by 2large bracts at base.Corolla 5-lobed, the 5 included stamens inserted on its tube; style with 2 oblong stigmas.Stem: Smooth or hairy, 3 to 10 ft.long, twining or trailing over ground.
Leaves: Triangular or arrow-shaped, 2 to 5 in.long, on slender petioles.
Preferred Habitat - Wayside hedges, thickets, fields, walls.
Flowering Season - June-September.
Distribution - Nova Scotia to North Carolina, westward to Nebraska.Europe and Asia.
No one need be told that the pretty, bell-shaped pink and white flower on the vigorous vine clambering over stone walls and winding about the shrubbery of wayside thickets in a suffocating embrace is akin to the morning-glory of the garden trellis (C.
