This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Native. Perennial. Propagates by seeds.
Time of bloom: May to June.
Seed-time: August to October.
Range: Massachusetts to Minnesota and Nebraska, southward to Alabama and Kansas.
Habitat: Rich soil; borders of fields, thickets, open woods.
A plant formerly in high esteem for its medicinal qualities, but now merely a weed. Stem two to four feet tall, erect, simple, softly hairy, and somewhat viscid. Leaves three to eight inches in length, opposite, joined at the base, ovate, pointed, entire, softly hairy, tapering to margined, connate petioles. Flowers axillary, sessile, single or clustered, brownish purple; corolla tubular, more than a half-inch long, with five unequal lobes, five stamens inserted on the tube, with bearded filaments and included anthers; style usually three-parted; calyx-lobes very narrow, long-pointed, persistent. Ovary three-celled, the fruit an orange-red drupe, nearly a half-inch long, containing three bony nutlets. (Fig. 280.)
Means of control Close cutting below the crown before any fruits mature.
Fig. 280. -Horse Gentian (Triosteum perfoliatum). X 1/4.