OEDEE 102. POLYGONACE^E. 603 



t 



form, limb spreading ; stamens 5, scarcely with the style exserted ; 

 aehenium enveloped in the persistent base of the calyx. 2 Herbs 

 mostly Mexican and Peruvian, everywhere cultivated. 



1 M. Jalapa L. Erect ; Ivs. ovate, acuminate, base obtuse or subcordate, pe- 

 tiolate, glabrous ; fls. 3 to 6 in each terminal fascicle, short-stalked; perianth open 

 in the evening and night. This is the true Four-o'clock, opening its multitudi- 

 nous brilliant flowers at about that hour P. M., for a long succession of summer 

 days. Their variety in color is infinite, f Peru. 



2 M. dichotoma L. Erect, glabrous ; Ivs. ovate, subacuminate, base obtuse 

 or narrowed to the petiole ; fls. sessile or nearly so ; lobes of invol. ovate-acute ; 

 perianth strict, with a small scarcely dilated limb. Gardens, less frequent. Fls. 

 smaller, yellow, red and white, f Mexico. 



3 M. longifldra L. "Weak, diffuse, viscid-pubescent ; Ivs. cordate-acuminate, 

 upper sessile, lower long-petioled ; fls. sessile, clustered at apex ; invol. lobes 

 linear; tube of the perianth very long, pubescent. Gardens. Fls. white, f Mexico. 



3. OXYB'APHUS, Vahl. (Gr. o^v(3d(j)ov, a shallow cup or saucer ; 

 alluding to the form of the involucre.) Involucre 5-cleft, containing 3 

 to 5 flowers (in one species), persistent and spreading in fruit ; perianth 

 with a very short tube, and a plicate, bell-shaped, deciduous limb ; 

 stamens 3 ; style simple, stigma capitate; fruit ovoid, ribbed, 1-seeded. 

 If! Herbs with tuberous roots, opposite Ivs. and small fls. (Caly- 

 menia, Allioni.) 



1 O. nyctagmeus Sweet. Nearly smooth, erect, with alternate or forked 

 branches ; Ivs. broadly ovate or oblong, subcordate, acute ; peduncles solitary, 

 axillary and terminal ; irivol. pubescent, 3 to 5-flowered. 2 Alluvial soils, Wis. 

 to Tenn., rare ; common in Nebraska. (Nuttall.) 



2 O. angiistifolius Sweet. St. terete, puberulent above, with alternate branches; 

 Ivs. narrowly lanceolate, thick but veiny, entire or serrulate, acute, narrowed to 

 tli3 subsessile base; ped. several times shorter than the leaves, axillary and termi- 

 nal ; invol. 3-flowered, half-5-cleft, lobes broad, obtuse ; ovary hispid. Dry soils 

 S. Car., Ga. to La. St. 2 to 3f high. Lvs. 2 to 3' by 5 to 9", or in some speci- 

 mens (A. linearis Ph.) much narrower. Ped. 2 to 5" long. Cal. purplish. Jn. 



3 O. albidus Sweet. St. angular, and pubescent in lines, simple; Ivs. narrow, 

 lance-oblong, acute at each end, petiolate ; ped. solitary, axillary, half as long as the 

 Ivs. ; invol. 2 to 3-flowered, deeply 5-cleft, segm. ovate, acute, ribs of fruit hispid. 

 <D Dry soils, S. Car., Ga. (Mettauer.) Sts. 12 to 18' high. Lvs. 2' to 30" long, 

 4 to G" wide. Ped. 1' long, alternate, each with a whitish involucre 10" broad 

 and 2 to 3 small fls. May. (A. alb. Ph.) 



3. BQERHAA'VIA, L. (Dedicated to Bcerhaave, of Holland, a friend 

 and patron of Linnaeus.) Involucre ; bractlets deciduous ; perianth fun- 

 nel or bell-form, colored, 5-lobed, upper half deciduous, lower persist- 

 ent ; stamens 1 to 4 ; fruit 5-ribbed, truncate at apex, 1-seeded. Lvs. 

 opposite, mostly petioled. 



B. erecta L. Glabrous; Ivs. ovate, wavy, pale beneath; fls. in a strict, much 

 branched panicle. (T) Sandy soils, S. Car. to Fla. and La. St. 3 to 4f high, nu- 

 merously dividing above into filiform, erect branchlets. Lvs. all below, 2' long, 

 roundish at base, on petioles nearly as long. Fls. minute. Jn. Sept. 



ORDER CII. POLYGONACEJi SORRELWORTS. 



Herbs, rarely shrubs, with alternate leaves and mostly sheathing stipules (ochrece) 

 surrounding the stem above each tumid joint. Flowers mostly perfect. Perianth 

 or calyx 3 to 6-cleft, mostly colored, imbricated in bud and persistent. Stamens 4 

 to 15, perigynous or free. Ovary 1-celled, free, with a single, erect ovule. Styles 

 or stigmas 2 or 3. Fruit a 3-angled aehenium enclosed in the calyx. Seed erect^ 



