Erect usually branched glaucous annual herbs, with opposite sessile or clasping entire leaves. Flowers large, blue, purple or white, long-peduncled, axillary and terminal, solitary or paniculate. Calyx deeply 5-6-cleft, the lobes lanceolate, acuminate, keeled. Corolla broadly campanulate, deeply 5-6-lobed, the lobes oblong or obovate, usually erose-denticulate, convolute in the bud. Stamens 5-6, inserted on the throat of the corolla; filaments filiform; anthers oblong, versatile, at length recurved, or remaining nearly straight. Ovary 1-celled; style filiform; stigma 2-lamellate. Capsule oblong or ovoid, 2-valved. Seeds small, numerous, foveolate. [Greek, open-mouth, referring to the corolla.]

Four species, natives of the southern United States, New Mexico and the West Indies. Type species: Eustoma silenifolium Salisb.

1. Eustoma Russellianum (Hook.) Griseb. Russell's Eustoma

Fig. 3346

Lisianthus Russellianus Hook. Bot. Mag. pl. 3626. 1839.

Lisianlhus glaucifolius Nutt. Trans. Am. Phil. Soc. (II.) 5:197. 1833-37. Not. Jacq. 1786.

E. Russellianum Griseb. in DC. Prodr. 9: 51. 1845.

Stem terete, rather stout, 1°-2 1/2° high. Leaves oblong or ovate-oblong, 3-5-nerved, the upper usually acute at the apex, cordate-clasping at the base, 1 1/2'-3' long, the lower usually obtuse at the apex and narrowed to a sessile or slightly auricled base; peduncles 1'- 4' long, stout, bracted at the base, the bracts lanceolate-subulate, small; flowers 2'-3' broad; calyx-lobes long-acuminate, shorter than the purple corolla; corolla-lobes obovate, about 4 times as long as the tube; style slender; anthers remaining nearly straight; capsule oblong, pointed.

On prairies, Nebraska to Louisiana, Colorado, Texas, New Mexico and Mexico. Canada pest. May-Aug.