A New Species of Platymiscium Vogel (Papilionoideae: Dalbergieae) from Costa Rica

Platymiscium curuense N. Zamora & Klitgaard (Papilionoideae: Dalbergieae), a new spe- cies from Costa Rica, is described and illustrated, and its taxonomic affinities are discussed. Platymiscium Vogel, a neotropical genus of ca. 18 species (Klitgaard, 1996), is represented in Cos- ta Rica by 5 species including the one described herein. While preparing an account of legumes for the Costa Rican Manual Project (first author) and a revision of Platymiscium (second author), a new species was discovered from the Pacific lowlands of Costa Rica. The new species belongs to a group with small flowers and pubescent inflorescence ra- chises, including P albertinae Standley & L. O. Williams, P parviflorum Bentham, and R hebes- tachyum Bentham. Arbor 15-30 m; ramuli teres, glabri. Folia 5-foliolata, elliptica vel angusto-elliptica et ovato-elliptica, apice ac- uminata, basi obtusa, glabra vel nitida utrinque, lamina (5-)6.2-17 cm longa, (2.2-)3.5-6.8 cm lata. Inflorescentia racemosa, 1.7-8.5 cm longa, rhachidibus dense tomento- so-pubescentibus, bracteis et bracteolis brevis, pilosis. Flores sessiles vel subsessiles, 7-9 mm longi; calyx 2-4 mm longus, campanulatus, glaber; petala aurea, vexillis 7-7.5 mm longis, 5-6 mm latis, orbiculatis. Stamina 10, monadelpha. Legumen planum, oblongum vel ellipticum, 9.7-13.5 cm longum, 3.3-3.8 cm latum, glabrum. Tree 15-30 m tall; straight bole, smooth bark, internodes of juvenile branchlets hollow or solid, glabrous; stipules deciduous, not seen. Leaves op- posite, 5-foliolate; leaf axis 5-11 cm long, rachis as long as or longer than petiole; leaflets elliptic, narrow-elliptic or ovate-elliptic, (5-)6.2-17 cm long, (2.2-)3.5-6.8 cm wide, apex acuminate, rounded or obtuse at the base, blade membrana- ceous, glabrous, and reticulate; petiolules 5 mm long. Inflorescence of short, erect, axillary, simple racemes, with up to 10 inflorescences per leaf axis; inflorescence axis thinly furrowed, often with per- sistent ledgelike pedicel scars (most easily visible on dried material), with matted whitish indumen- tum, axis 1.7-8.5 cm long, including a peduncle (0.5-)1.5-2 cm long, racemes up to 40-flowered. Flowers (5-)7-9 mm long, pedicels to 2 mm long, slender, hairy, persistent, without food bodies ba- sally; bracts spathulate, 1 x 0.5 mm, caducous be- fore anthesis, hairy; calyx campanulate, 2-4 mm long, articulated from pedicel, base acuminate, ro- bust, glabrate, brown, 5-toothed, two vexillary teeth connate to 2/3 their length, the other three similar to each other with obtuse apices, pubescent along margins of the teeth; corolla yellow, standard or- bicular, heart-shaped, 7-7.5 mm long, 5-6 mm wide, clawed, wing petals 8-8.5 mm long, 3 mm wide, short-clawed, with sculpture pattern basally along upper margin; keel petals 7-7.5 x 3 mm, long-clawed, adnate along ca. ?2 of lower margins, free part of margins sparsely ciliate; androecium monadelphous, 9 stamens fused progressively high- er abaxially, the vexillary stamen only fused basal- ly; anthers dimorphic; ovary long-stipitate, ciliate along margins of suture. Fruit a samara, elliptic to oblong, 9.7-13.5 x 3.3-3.8 cm, acuminate at both ends, glabrous, exocarp rusty brown at maturity; stipe 10-11 mm long. This new species is related to Platymiscium al- bertinae, P parviflorum, and P hebestachyum be- cause of its small flowers and tomentose inflores-