Family 16. TRIGONIACEAE * 



By Paul Carpenter Standley 



Trees or shrubs, usually scandent or subscandent, the branehlets terete or 

 angulate. Leaves opposite or alternate, simple, entire, penninerved. .Stipules 

 usually present, large, interpetiolar, sometimes connate. Flowers perfect, 

 small, irregular, bibracteolate, racemose or paniculate. Sepals 5, free or 

 connate at base, subequal, imbricate in bud, deciduous. Petals 3 or 5, white 

 or pink, free, subperigynous, alternate with the sepals, unequal and somewhat 

 papilionaceous, contorted in bud. Stamens 5-12, 2-6 of the fertile ones united, 

 the tube cleft on one side; filaments filiform; anthers 4-celled, oval, opening by 

 longitudinal introrse slits. Disk sometimes present between the middle petal 

 and androecium. Ovary free, 3-celled; style terminal, simple; stigma capitate 

 or obliquely truncate; ovules 2 or more in each cell, biseriate, attached to a 

 central placenta, anatropous. Fruit capsular, 3-celled, septicidally 3-valvate, 

 the valves separating from the central column and themselves often separating 

 into endocarp and epicarp. Seeds 2 or more in each cell, the testa thin, 

 covered with long wool; endosperm fleshy; embryo straight, the cotyledons 

 plane, thin, the radicle short. 



1. TRIGONIA Aubl. PI. Guian. 387. 1775. 



Nuttallia Spreng. Neue Entdeck. 2: 158. 1821. 

 Mainea Veil. Fl. Flum. 275. 1825. 



Scandent or reclinate shrubs. Leaves opposite, short-petiolate, usually white-tomentose. 

 Stipules interpetiolar, deciduous, simple or bifid at apex, or free. Flowers small, in terminal 

 panicles or compound racemes. Sepals connate at base, unequal, the 2 inner ones larger. Petals 

 5, very unequal, the posterior one largest, spurred or saccate, pilose in the throat of the spur, 

 the blade reflexed, the 2 anterior ones ascending, inequilateral, narrow, barbate above the base, 

 the other 2 smaller, approximate and keel-like. Stamens 10, but usually only 6 of them fertile, 

 opposite the anterior petals; 2-4 hypogynous glands or a crenate crest present opposite the 

 posterior petal. Ovary ovoid or subglobose, attenuate to the style, hirsute; stigma obliquely 

 truncate; ovules several or numerous, pendulous from the axis. Capsule 3-angulate, usually 

 hairy outside and often also within. Seeds several in each cell, compressed-globose. 



Type species, Trigonia villosa Aubl. 



Leaves broadly rounded or subcordate at base. 1. T. etiryphylla. 



Leaves acute or obtuse at base 1 . 2. T. jloribunda. 



1. Trigonia euryphylla Standley, sp. nov. 



Young branches densely floecose-tomentose with white or fulvous tomentum, glabrate in 

 age, the internodes 4 cm. long or less; stipules triangular-ovate, 3-4 mm. long, obtuse, cadu- 

 cous, fulvous-tomentose; petioles stout, 4-12 mm. long, floecose-tomentose; leaf-blades oval 

 or oblong-oval, 4-10 cm. long, 2-5 cm. wide, rounded to acute at apex, broadly rounded or 

 subcordate at base, chartaceous, pale-green above, floecose-tomentose along the nerves, beneath 

 densely covered with a close dense white floccose tomentum, the costa and lateral nerves prom- 

 inent, the latter about 9 pairs, arcuate-ascending, anastomosing near the margin; inflorescence 

 thyrsoid-paniculate, much exceeding the leaves, in age glabrate, the ultimate cymules dichot- 



* Published by permission of the Secretary of the Smithsonian Institution. 



Volume 25, Part 4, 1924] 297 



