This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Native. Annual. Propagates by seeds.
Time of bloom: May to September.
Seed-time: June to October.
Range: Michigan to California, southward to Mexico, Texas, and
Florida. Habitat: Sandy, alluvial soils; fields, gardens, waste places.
Fig. 185. -Three-seeded Mercury (Acalypha virginica).
A common, worthless, and prolific little plant, not so much detested as it deserves to be, for it and all its kindred are more or less poisonous, their growth serving merely to impoverish the ground and befoul it with seeds for another generation.
Stem four inches to a foot in length, branching from the base, declining or prostrate, slender, smooth, usually green on the under side but red where exposed to the light, filled with a poisonous milky juice. Leaves also reddish or red-spotted, opposite, less than a half-inch long, obovate or spatulate, obtuse, unequal-sided, finely and sharply toothed for about half their length, short-petioled, with narrow stipules ending in a fringe of weak bristles. Spurge flowers have neither calyx nor corolla, but are monoecious after an odd fashion; there is a funnel-shaped involucre on a short terminal peduncle, in this case appearing lateral but not really axillary, bearing four small, disk-like glands, each subtended by a narrow, toothed appendage; within the involucre are several male flowers, each consisting of a single stamen on a pedicel subtended by a tiny bract; fertile flower a single three-celled, three-styled, and three-seeded ovary, at first in the bottom of the involucre but soon thrust out on a slender stipe and ripening in the outer air into a nodding capsule with three carpels, each holding one seed; in this species the latter are hardly one-twelfth of an inch long, sharply four-angled, the faces cross-wrinkled and pitted.
Means of control the same as for the ubiquitous Spotted Spurge.