Trans. i. 384.-Schoepf. 24.-Wedenberg in Med. Comment iii. 18.—BEVERLY, Hist. Virg. p. 121.-Medical and Physical Journal, vol. xxv. & xxvi. in various places. CoOPER in Caldwell's Theses, vol. i.-BARTON, Coll. Mat. Med. 46.-CHAPMAN in edit. MURRAY 146.-THATCHER, Disp. 205.-MARCET Medico-Chirur. Trans. vii.

PLATE I.

Fig. 1. A branch of Datura Stramonium, the purple variety, with leaves and flowers.

Fig. 2. Stamens and style.

Fig. 3. Transverse section of the pericarp, shewing the cells, receptacles and seeds.

EUPATORIUM PERFOLIATUM.

Thorough wort.

PLATE II.

THE peculiar form and arrangement of the leaves in this plant render it very easy of distinction at sight by the most inexperienced botanist. It flowers from midsummer to September, and is found in all latitudes from Nova Scotia to Florida. It inhabits meadows and boggy soils, growing most frequently in bunches, the stems being connected by horizontal roots. Its common names are Thorough wort, Thorough wax, Cross wort, Bone set, &c.

The genus Eupatorium, belonging to the first order of the class Syngenesia or Compound flowers, and to the order Corymbiferæ of Jussieu, is characterized by its naked receptacle, its down simple or rough, its calyx oblong and imbricate,

its style longer than the corolla, and cloven half way down. The species perfoliatum, exclusively an inhabitant of America, is abundantly distinguished from the rest, by the peculiar form of its leaves, indicated in its name. Michaux has altered the specific name to connatum I think injudiciously.

The stems of this plant are erect, round, hairy branched at top only. The leaves, which are perforated by the stem, are rather perfoliate than connate, since they have not the character of two leaves joined together, but of one entire leaf, having its four principal veins proceeding at right angles from the four quarters of the stem, two of them being situated in the place of the supposed junction. The upper leaves however are generally divided into pairs. The main leaves are acuminate, decreasing gradually in breadth from the stem, where they are widest, to the extremities. They are serrated, wrinkled, pale underneath, and hairy, especially on the veins. Flowers in corymbs with hairy peduncles. Calyx cylindrical, imbricate, the scales lanceolate, acute, hairy. Each calyx contains about twelve or fifteen florets, which are tubular, with fine spreading segments, and surrounded with a rough down. The stamens-in each consist of five soft filaments, with blackish anthers