Low usually acaulescent herbs, rarely producing short stems. Leaves mostly basal, pinnatifid, numerous. Flowers perfect, white, pink or pale yellow. Calyx-tube slender, dilated at the throat; calyx-segments finally reflexed, the tips free in the bud or united. Petals 4, spreading. Stamens 8, the alternate ones longer; filaments filiform; anthers linear. Ovary short, 4-angled; stigma 4-cleft; ovules few. Capsules stout, their angles sometimes winged above. Seeds few. [In honor of Francois Delavaux, founder of the botanical garden at Nismes.]

About 6 species, chiefly in southern North America. Type species: Lavauxia triloba (Nutt.) Spach.

Leaves membranous; capsules beaked, glabrate.

1.

L. triloba.

Leaves leathery; capsules hardly beaked, pubescent.

2.

L. brachycarpa.

I. Lavauxia Triloba (Nutt.) Spach. Three-Lobed Primrose

Fig. 3059

Oenothera triloba Nutt. Journ. Acad. Phil. 2: 118. 1821.

Lavauxia triloba Spach, Hist. Veg. 4: 367. 1835.

Perennial, nearly glabrous throughout. Leaves petioled, runcinate-pinnatifid, sometimes cili-ate, oblong-lanceolate in outline, 3'-12' long, sometimes 2' wide, the apex acute or acutish; flowers white or pink, l'-2 1/2' broad; calyx-lobes lanceolate, spreading, the tube slender, somewhat dilated at the summit, many times longer than the ovary, 2'-4' long; petals often 3-lobed; capsule ovoid, 4-wing-angled, reticulate veined, 6"-12" long; seeds finely and densely tubercu-late.

In dry, often rocky soil, Kentucky and Tennessee to Kansas, Utah and California, south to Mississippi, Texas and northern Mexico. May-July.

Lavauxia WÓtsoni (Britton) Small, of Kansas and Nebraska, is described as differing from this species in being annual with smaller flowers and more abundant fruit. (Oenothera triloba var. parviflora S. Wats.)

I Lavauxia Triloba Nutt Spach Three Lobed Primrose 1401

2. Lavauxia brachycÓrpa (A. Gray) Britton. Short-podded Primrose.

Fief. 3060.

Oenothera brachycarpa A. Gray, Pl Wright. 1: 70. 1852.

Lavauxia brachycarpa Britton, Mem. Torr. Club 5: 235. 1894.

Low, perennial by a stout root, acaulescerrt or nearly so, softly canescent. Leaves basal, leathery, ovate to narrowly oblong, 3'-9' long, acute or obtuse, lyrate-pinnatifid or sometimes nearly entire; petioles sometimes as long as the blade; flowers yellow, basal; calyx canescent, its tube 2'-4' long, gradually dilated upward, its segments linear-lanceolate, about one-half as long as the tube, the tips free in the bud; petals 1'-1 1/2' long, undulate; capsules elliptic, 8"-9" long, leathery or corky, the angles very thin, the faces somewhat wrinkled.

Montana to Kansas, Texas and New Mexico. April-July.

I Lavauxia Triloba Nutt Spach Three Lobed Primrose 1402