NYCTAGINACE^E. (FOUR-O'CLOCK FAMILY.) 373 



Stamens 3, exserted. Style slender : stigma capitate. Achenium enclosed in 

 the indurated ribbed persistent base of the calyx. Erect herbs, from thick 

 perennial roots. Leaves opposite. Flowers terminal, purple or rose-color. 



1. O. angustifolius, Sweet. Stem smoothish, branching above; leaves 

 linear-lanceolate, smooth, obtuse at the sessile base; the upper ones distant, 

 acute; flowers loosely panicled; involucre with rounded hairy lobes, at length 

 enlarged and strongly nerved, 3-flowered ; base of the calyx villous. South 

 Carolina, and westward. Stem 3 -4 high. Leaves 2' long. Calyx 4"- 5" 

 long, whitish, veiny. 



2. O. albidus, Sweet. Stem erect, 4-angled, furrowed, glandular, pubes- 

 cent ; branches opposite ; leaves oblong-lanceolate, roughish ; peduncles oppo- 

 site, the lower ones solitary, the upper clustered ; involucre hairy ; base of the 

 calyx 5-6-angled, almost hispid. (Allionia albida, Ell.) Near Columbia, 

 S. C., Elliott. 



2. BOERHAAVIA, L. 



Flowers perfect, Involucre none. Calyx-tube cylindrical or obconical, 5- 

 ribbed; the limb colored, funnel-shaped, 5-lobed, deciduous. Stamens 1-4: 

 anthers minute, roundish. Style slender: stigma obtuse. Embryo folded. 

 Annual herbs, with diffuse branching stems, and opposite ovate or rounded 

 leaves. Flowers small, in solitary or panicled clusters. 



1. B. erecta, L. Stems ascending, branched from the base, smooth, tumid 

 at the joints ; branches alternate ; leaves ovate or roundish, acute or mucronate, 

 often more or less cordate, wavy along the margins, whitened and minutely dot- 

 ted with black beneath ; clusters 3 - 5-flowered, in ample panicles ; stamens 2 ; 

 fruit smooth, obconical, truncate, strongly ribbed. Cultivated ground, Florida 

 to South Carolina. July - Sept. Stem l-3 long. Leaves rather thick, 

 2' -3' long. Flowers small, purple. 



2. B. hirsuta, Willd. Stem diffuse, alternately branched, minutely pubes- 

 cent, hirsute above ; leaves ovate or oblong-ovate, mucronate, obtuse at the base, 

 undulate, smooth, and similarly colored on both sides, ciliate on the margins ; 

 clusters 3 - 6-flowered, forming a loose spreading panicle ; flowers minute ; calyx- 

 limb hairy at the apex ; fruit obconical, rounded at the apex, with the ribs gland- 

 ular-viscid. South Florida. Stem stout, 2 - 3 long. Leaves 1' - 2' long. 



3. B. viscosa, Lag. Viscid or minutely pubescent ; stem terete, straight ; 

 branches opposite ; leaves ovate-oblong or ovate-lanceolate, mucronate, acute at 

 the base, smooth, whitish beneath, slender-petioled ; peduncles solitary, axillary, 

 2-cleft, mostly shorter than the leaves ; flowers capitate, minute ; stamens 3 ; 

 fruit club-shaped, acutish, with the ribs glandular. South Florida. Stem 2- 

 3 long. Leaves I'- l' long. 



3. PISONIA, Plum. 



Flowers dioecious. Involucre none. Calyx 5- or 10-toothed, funnel-shaped in 

 the sterile flowers, tubular and persistent in the fertile. Stamens 6-10, exserted : 

 32 



