372 NYCTAGINACE.E. (FOUR-O'CLOCK FAMILY.) 



twining herbs or shrubs. Leaves alternate, cordate at the base. Flowers long- 

 peduncled, axillary, or near the base of the stem. 



* Low herbs. 



1 . A. Serpentaria, L. Stems single or clustered, pubescent, zigzag and 

 leafy above ; leaves short-petioled, varying from ovate to linear-lanceolate, cor- 

 date or hastate at the base ; flowers near the base of the stem, on bracted spread- 

 ing peduncles ; calyx tortuous, 3-lobed, dull purple. (A. hastata, Null.) Shady 

 woods, Florida to Mississippi, and northward. June -Aug. Stem 8' -12' 

 high. Leaves 2' -4' long. Calyx shaped like the letter S. 



* * Woody vines : capsule oblong, six-angled, 3' - 4' long. 



2. A. Sipho, L'Her. Stem smoothish ; leaves large, orbicular-cordate, 

 slightly pubescent beneath ; peduncles slender, solitary, with a roundish clasping 

 bract near the base ; calyx curving upward, with the broad spreading brownish- 

 purple border obscurely 3-lobed. Rich woods along the mountains, Georgia, 

 and northward. May. Stem climbing high. Leaves 6' -12' broad. Calyx 

 shaped like a Dutch pipe, 1 ' long. 



3. A. tomentosa, Sims. Hoary-pubescent ; leaves cordate ; peduncles 

 opposite the leaves, bractless, woolly ; calyx bent in the middle, the greenish 

 rugose unequally 3-lobed border reflexed, thickened and dark brown at the 

 nearly closed throat. ; River-banks, Florida, to the mountains of North Caro- 

 lina, and westward. May. Stem very long. Leaves 3' - 5' long. Calyx 

 similar in shape to the preceding, but smaller. 



ORDER 106. NYCTAGTNACE^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 por- 

 tion deciduous. Stamens 1 - several, hypogynous : anthers 2-celled, round- 

 ish. 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. Cotyle- 

 dons 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. 



