NYCTAGINACEiE. (fOUR-O'cLOCK FAMILY.) 393 



* * Stamens 5. 

 4. A. pentandra, L. Perennial, herbaceous, smoothish ; stem pros- 

 trate or twining ; leaves ovate, cordate ; flowers axillary ; limb of the calvx 

 lanceolate, acuminate, deep green, much longer than the 5-angled tube. — 

 Miami, South Florida (Garher). 



Order 105. NYCTAGINACE^E. (Four-o'clock Family.) 



Herbs or shrubs with tumid joints. Leaves mostly opposite, simple, 

 petioled, without stipules. — Calyx colored and resembling a corolla, 

 tubular-bell-shaped or funnel-shaped, free from the 1-celled and 1- 

 ovuled ovary, plaited in the bud, contracted in the middle, with the 

 upper portion deciduous. Stamens 1- several, hypogynous: anthers 

 2-celled, roundish. Ovule erect. Style simple : stigma simple or 

 branched. Achenium enclosed in the indurated, mostly ribbed, often 

 glandular base of the calyx. Embryo coiled or folded around copious 

 mealy albumen. Cotyledons leafy. Radicle inferior. 



Synopsis. 



* Flowers surrounded by a calyx-like involucre. 



1. OXYBAPHUS. Involucre open, membranaceous, 5-lobed. Herbs. 



* * Flowers without an involucre. 



2. BOERHAAVIA. Flowers perfect. Embryo coiled. Herbs. 



3. PISONIA. Flowers dioecious. Embryo straight. Shrubs. 



1. OXYBAPHUS, Vahl. 



Flowers perfect, 1 - 5 in a cluster, surrounded by an open cup-shaped 5-lobed 

 involucre. Calyx tube very short ; the bell-shaped limb 5-lobed, deciduous. 

 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, whiti.sh, veiny. 



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

 bescent; branches opposite; leaves oblong-lanceolate, roughish; peduncles 

 opposite, the lower ones solitary, the upper clustered ; involucre hairy ; base 

 of the calyx 5-6-angled, almost hispid. (AUionia, EU.) — Near Columbia, 

 South Carolina (Elliott). 



3. O. nyctagineus, Sweet. Stem smoothish, 4-angled, forking ; leaves 

 petioled, deltoid-ovate ; flowers clustered, terminal ; involucre 3 - 5-flowered, 

 becoming large and veiny. — West Tennessee, and westward. July -August. 

 — Stem 1°- 2° high. 



