May. Sterile stems produced: All summer. Range: American continent from
Greenland to Alaska, southward to
Virginia and California. Habitat: Damp grasslands, moist road embankments.
In early spring one may note large colonies of the fertile stems of these plants, mere cylindrical, light brown, leafless stalks, four to eight inches high, jointed, hollow, and tipped with yellowish, club-shaped, spore-bearing heads. Each joint is ridged and grooved and edged with a brown sheath, notched with eight to a dozen teeth. The joints readily pull apart. These early, fertile plants scatter their spores to the winds and wither and die in a few weeks. But later, from
Fig. 3. - Field Horsetail (Equisetum arvense). X 1/4 the same perennial, creeping, jointed, and branching rootstocks, spring the green, plume-like, sterile stems known as Horsetails (Fig. 3). These are eight inches to more than a foot tall, also hollow and jointed, but having whorls of simple rough branches issuing from the base of each sheath; the branches are usually four-angled, but sometimes have only three sides, and are jointed but not hollow. These green Horsetails are the food-assimilating, starch-making parts of the plant and keep busy all summer, storing the creeping rootstocks with nutriment for the next year's fruiting stems.
The Horsetail is poisonous - most dangerously, sometimes fatally, so to horses, and in a much less degree to sheep, causing in the flocks merely a thin, unthrifty appearance and lack of good condition. Strangely enough, neat cattle seem to be able to digest the weed without injury. The state of Vermont, where horse-raising is so great an industry, credits to this plant a loss of some thousands of dollars annually.
Drain, fertilize, and cultivate the ground. The plant thrives best in sandy or gravelly soil that is moist during the early part of the season, or where the soil water approaches near the surface.* Drainage, and two or three seasons of good, thorough tillage, will drive it out; for, though the rootstocks are deeper in the ground than ordinary cultivation penetrates, yet they will starve and die if kept deprived of the green, food-assimilating, sterile stems. Plants of waste places should receive attention, to the destruction of both fertile and sterile shoots, as the wind-carried spores may start new infestations.