This section is from the book "The Gardener's Monthly And Horticulturist V20", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
I have been watching with interest for some days the visits of flies to the Asclepias Cornuti, Decaisne, common Milkweed or Silkweed, the house fly, a large green one, and another having the appearance of a flying ant. They light on the centre of the flowers, putting their probosces in every hood behind the horn. While doing so, if not careful, the hind leg will get caught in the slit between the hoods, and in the effort to extricate itself, the limb will often leave the leg behind.
T was fortunate at last to see a fly, one of the former (the two latter do not seem apparently to have any sucb difficulty, but light and fly away at pleasure, ) light and carry off a pair of pollen masses attached to its leg. It visited several flowers before 1 was successful in capturing it. The flitting from flower to flower with the pollen, proves to my mind the manner in which the plant is fertilized; the slit is an ingenious trap. The large green flies were more numerous than the others.
I see that Dr. G. F. Walters, of Boston, has found in the juice of the Milkweed a remedy for suppurating wounds. The time of healing varied from twenty-four to thirty-six hours, but in each instance new skin formed completely across. The Doctor states that the only essential point is to dry the wounded surface gently and thoroughly with blotting-paper before applying the Milkweed juice. After the juice is applied, and while the healing is in progress, a piece of blotting-paper is used to cover the surface.
[The catching of flies, as referred to by our correspondent, is alluded to by Nuttall in one of his works, written over fifty years ago, but seems to have been forgotten. For what purpose such traps are made is an interesting study. Many Asclepiadaceous plants have the same habit. Physianthus albens is a striking example, quite large moths often being found hanging from the flowers as caught. - Ed. G. M].
Mrs. M. writes: "Perhaps it may be interesting to your readers in connection with the A. cornuti, that the plant which stood about two feet and a half high bore three pods or follicles; they generally fruit in pairs. The plant had five clusters of flowers, consisting of from thirty to sixty blooms. I gathered one, leaving four to mature. Wood says but few of the flowers prove fertile; more could not in the space. The pods measure three inches long, one inch in diameter. They average about two hunched and twenty seeds; the three, as near as I could count, had six hundred and sixty-eight seeds, sufficient for a plant of it size".