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. BOEBHAAVIA, 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. hirsute, 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 1'- U' long. 



3. PISONIA, Plum. 



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

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

 32 



