RUBIACEAE. SILVA OF NORTH AMERICA. 103 
EXOSTEMA. 
FLowWERS perfect ; calyx-limb 5-toothed ; corolla gamopetalous, 5-lobed, quincun- 
cially imbricated in estivation ; stamens 5; ovary 2-celled ; ovules numerous, ascending. 
Fruit a 2-celled many-seeded crustaceous capsule. Leaves opposite, simple, stipulate, 
persistent. 
Exostema, Richard, Humboldt & Bonpland Pl. Aquin. i. 491 (excl. Badusa). — Engler & Prantl, Pflanzenfam. iv. 
131 (1808). — A. Richard, Mém. Soc. Hist. Nat. Paris, pt. iv. 53. 
v. 200. — Meisner, Gen. 158. — Endlicher, Gen. 555.— Solenandra, Hooker f. Hooker Icon. xii. t. 1150 (1876). — 
Bentham & Hooker, Gen. ii. 42. — Baillon, Hist. Pl. vii. Bentham & Hooker, Gen. ii. 438. 
Trees or shrubs, with usually terete branchlets, bitter bark, and watery juice. Leaves opposite, 
simple, sessile or petiolate, persistent ; stipules interpetiolar, entire, denticulate or two-parted, deciduous. 
Flowers axillary, solitary or in many or few-flowered terminal panicles, large or small, fragrant, pedun- 
culate, the peduncles bibracteolate above the middle. Calyx-tube ovoid, clavate, or turbinate, the limb 
short, five-lobed, its lobes nearly triangular, subulate or linear, persistent or deciduous. Corolla white, 
funnel-shaped, the tube long and narrow, erect, glabrous or pilose in the throat, the lobes of the limb 
linear, elongated, spreading. Stamens five, alternate with the lobes of the corolla, exserted ; filaments 
filiform, united at the base into a short or long tube inserted on and adnate to the tube of the corolla; 
anthers oblong, linear, attached at the base, two-celled, the cells opening longitudinally. Disk epigy- 
nous, annular. Ovary inferior, two-celled ; style simple, elongated, slender, exserted ; stigma capitate, 
simple or minutely two-lobed ; ovules numerous, attached on the two sides of a fleshy oblong peltate 
placenta fixed to the inner face of the cell, ascending, anatropous ; raphe ventral; micropyle superior. 
Fruit capsular, many-seeded, cylindrical or clavate, two-celled, septicidally two-valved, the valves entire 
or two-parted ; epicarp membranaceous, separable from the crustaceous endocarp. Seeds compressed, 
ovate or oblong, rounded or pointed at the apex, imbricated downwards on the placenta ; testa membra- 
naceous, chestnut-brown, lustrous, produced into a narrow wing. Embryo minute, in fleshy albumen ; 
cotyledons flat ; radicle terete, inferior. 
Exostema is confined to the tropics of America, where about twenty species, chiefly found in the 
Antilles,’ are distributed from southern Florida, where one species occurs, to Mexico, Central America, 
and Brazil.’ 
The bark of Exostema contains active tonic properties. That of several species, especially of 
Exostema Caribeum and Exostema floribundum,’ was considered a useful febrifuge® before the 
general introduction of the more valuable Cinchona barks, which now replace it except in domestic 
practice in the countries which Exostema inhabits. 
The generic name, from éo and oryjua, relates to the long exserted stamens. 
1 A. Richard, Fl. Cub. iii. 5.—Grisebach, Fl. Brit. W. Ind. 323 ; Cinchona floribunda, Swartz, Prodr. 41 (1788) ; Fl. Ind. Oce. 
Cat. Pl. Cub. 125. 375. — Lambert, Cinchona, 27, t. 7. — Poiret, Lam. Dict. vi. 37. 
2 Orsted, Videnskab. Medd. fra Nat. For. Kjobenh. 1852, 26. — Cinchona montana, Badier, Rozier Obs. xxxiv. 129, t. 1 (1789). — 
Gray, Proc. Am. Acad. v. 180. — Hemsley, Bot. Biol. Am. Cent. ii. 13. Descourtilz, FZ. Méd. Antill. i. 57, t. 13. 
8 Poeppig & Endlicher, Nov. Gen. et Spec. iii. 31, t. 231. — Schu- Cinchona Luciana, Vitman, Summa Al. Suppl. 264 (1802). 
mann, Martius Fl. Brasil. vi. pt. vi. 192. 5 Davidson, Phil. Trans. Ixxiv. 452.— Fourcroy, Ann. de Chim. 
4 Roemer & Schultes, Syst. v. 19 (1819). — Hayne, Arzn. vii. t. viii. 113. — Lunan, Hort. Jam. i. 391.— A. Richard, Hist. Nat. 
45.— De Candolle, Prodr. iv. 360.— A. Richard, /. c. 6.— Grise- Méd. iii. 530. —Guibourt, Hist. Drog. ed. 7, iii. 186. — Rosenthal, 
bach, J. c. Syn. Pl. Diaphor. 337. 
