Jimson weed

In 1676 British soldiers stationed in Jamestown, Virginia became intoxicated by Datura stramonium when it was inadvertently included in their salads by the regimental cooks. The episode was widely publicized and the plant culprit became known as "Jamestown weed", and later as jimsonweed.

The nocturnal blossoms and pollination ecology of Datura are among the most ingenious and unusual of all wildflowers of western North America. The entire corolla is neatly folded or pleated (plicate) and twisted (convolute) in the bud forming a compact cylinder. Each day at dusk during the summer months the buds begin to gradually unfold. Each corolla slowly unfurls and then suddenly snaps open as the intertwined lobes come loose from one another. At this instant a powerful fragrance is emitted.

Five long stamen filaments are attached to the funnelform corolla at the throat. The filaments extend as ridges down the inner corolla tube, forming 5 narrow canals to the base of the ovary where the disc-shaped nectary is located. The nectar canals can best be seen by examining a corolla tube in cross section. The curious name "revolver flower" refers to nectar canals which resemble the cylinder chambers of a 5-shot revolver. At night the nectar oozes along the length of the canals within the corolla tube.

During mid and late summer the white, fragrant blossoms are frequently visited by large nocturnal hawk moths (family Sphingidae). They are sometimes called Sphinx Moths because the alarm posture of the larva resembles the Egyptian sphinx. Several species of hawk moths are known to visit blossoms of Datura, but two of the most common are Manduca quinquemaculata and M. sexta. The larval forms of both are better known as tomato and tobacco hornworms.

Since Datura, tomatoes and tobacco all belong to the Nightshade family (Solanaceae), the larvae are apparently content to feed on whichever plant is available to them. The larvae are remarkably camouflaged with green markings and are difficult to spot as they rapidly devour your tomato plants. After feasting on Datura (or your tomato plants) all summer, the robust, ravenous caterpillars crawl to the ground and burrow into the soil where they undergo pupation. Unlike many other moth larvae they do not spin a cocoon. Probably every tomato gardener has unearthed the large, carmel-colored pupa with its peculiar "jug handle" appendage, which is actually a case for the developing proboscis of the adult moth.

Another fascinating aspect of the Grant's research concerns a rather unconventional type of floral reward for hawk moths visiting Datura blossoms. Several intoxicating alkaloids are known to occur in Datura, but heretofore have not been correlated with pollination. Apparently Datura nectar is "spiked" with alkaloids and the hawk moths seem to like it and come back for more. Sometimes they arrive early and hover around the flowers, impatiently waiting for the blossoms to "pop" open. Intoxicated moths have been observed flying erratically around Datura clumsily landing on blossoms and crashing into leaves or falling upon the ground.