Part 2, 1921] RUBIACEAE 117 



3. Hillia panamensis Standley, sp. nov. 



Epiphytic shrub, glabrous throughout, the branches slender, brownish, the branchlets 



with short internodes; stipules linear-oblong, 3-4 mm. long, obtuse, brownish; petioles stout, 



1-2 mm. long; leaf-blades linear-oblong or elliptic-linear, 7-12 mm. long, 2-3 mm. wide, acute 



at the base, obtuse or rounded at the apex, subcoriaceous, bright-green, concolorous, the costa 



obsolete above, prominulous beneath, the margin subrevolute; flowers short-pedicellate; 



capsule linear-oblong, 1-2.5 cm. long, brown, the valves 5-6 mm. wide; seeds numerous, 



elliptic-oblong, 2 mm. long, brown, bearing at the apex numerous brown hairs 5-6 mm. long. 



Type collected in the humid forest around Los Siguas Camp, southern slope of Cerro de la 

 Horquetu, Chiriqui, Panama, altitude 1700 meters, March, 1911, H. Pitlier 3190 (U. S. Nat. Herb. 

 no. 677584). 



38. EXOSTEMA* Rich.; Humb. & Bonpl. PI. Aequin. 

 1: 131. 1908. 



Solenandra Hook. f. in Hook. Ic. 12: 45. 1876. 

 Sleudelago Kuntze, Rev. Gen. 298. 1891. 



Shrubs or trees, glabrous or pubescent, the branchlets usually terete. Leaves opposite, 

 petiolate or subsessile, the blades large or small, membranaceous or coriaceous. Stipules 

 interpetiolar, entire or bifid, deciduous or persistent. Flowers small or large, axillary and 

 solitary or arranged in terminal panicles or corymbs, white, red, or yellow, pedicellate, brac- 

 teolate or ebracteolate ; hypanthium cylindric or obovoid; calyx 5- (rarely 4-)lobate, the lobes 

 broad or narrow; corolla short or elongate, the tube elongate, often very long, the throat 

 glabrous or pilose, the limb 5-(rarely 4-)lobate, the lobes oblong or linear-elongate, imbricate, 

 2 of them exterior. Stamens 5, inserted at the base of the corolla-tube; filaments filiform, 

 elongate; anthers basifixed, linear, usually exserted. Disk annular. Ovary 2-celled; style 

 filiform, usually exserted; stigma capitate, entire or bilobate; ovules numerous, ascending, 

 the placentae adnate to the septum. Capsule usually oblong-cylindric, 2-celled, septicidally 

 bivalvate, the valves entire or bipartite. Seeds usually numerous, imbricate, the body ob- 

 long, compressed, the testa membranaceous, produced into a wing; endosperm fleshy; embryo 

 small, the radicle terete, inferior. 



Type species, Exostema parviflorum Rich. 



Stamens included; corolla-lobes short, rounded. 1. E. Coulter i. 



Stamens exserted ; corolla-lobes linear or oblong. 



Inflorescence 1-flowered, rarely 2-3-flowered, axillary or rarely terminal. 

 Leaf -blades very small, 3-8 mm. long; branchlets spinose; flowers 4- 



parted. 2. E. spinosum. 



Leaf-blades 2 cm. long or usually much longer; branchlets not spinose; 

 flowers 5 -parted. 

 Calyx-lobes linear or subulate, 2-6 mm. long; corolla-tube 12-14 

 cm. long. 

 Leaf -blades coriaceous, obtuse at the apex; branchlets glabrous; 



flowers terminal. 3. E. stenophyllum. 



Leaf -blades membranaceous, attenuate at the apex; branch- 

 lets puberulent or villosulous when young; flowers mostly 



axillary. 4. E. longiflorum. 



Calyx -lobes 1 mm. long or shorter, triangular; corolla-tube 1.5-5 

 cm. long. 

 Leaf-blades obtuse at the apex, 7-1 1 mm. wide, sessile or nearly 



so. 5. E. salicifolium. 



Leaf-blades acute or acuminate at the apex. 



Corolla-tube 1.5-2.5 cm. long; leaves coriaceous or charta- 

 ceous, the lateral veins mostly obsolete beneath. 

 Corolla-tube 2-2.5 cm. long, the lobes about twice as 



long; leaf-blades lanceolate or ovate-lanceolate. 6. E. acuminatum. 



Corolla-tube 1.5 cm. long, the lobes of about the same 

 same length; leaf -blades mostly ovate or elliptic- 

 oblong. 7. E. purpureum. 

 Corolla-tube 3-5 cm. long; leaves membranaceous, the 



lateral veins conspicuous beneath. 8. E. caribaenm. 



Inflorescences few- or usually many-flowered, all or chiefly terminal. 

 Corolla glabrous outside. 



Corolla 2.5 cm. long or longer; anthers usually 8-12 mm. long. 



Hypanthium pubescent; leaves linear-lanceolate. 9. E. angustijolium. 



Hypanthium glabrous; leaves oblong or ovate or broader. 



* Sometimes written Exostemma. 



