Amyris oblanceolata (Rutaceae), a New Species from Nicaragua

Abstract

Amyris oblanceolata, a new species from northwestern Nicaragua, is described, and its relationships to other Central American species with opposite, trifoliolate leaves are discussed. The genus Amyris consists of approximately 40 species distributed in the West Indies and from Florida and Texas through Central America to Peru and Venezuela. They are unarmed trees or shrubs with the leaves opposite, or alternate, and 1-11-foliolate; the flowers small, generally perfect and actinomorphic with 3-5 petals and 6-10 free stamens; and the fruits one-seeded drupes. Species found in South America were revised by Gereau (1991). A new species of Amyris from Central America was encountered during preparation of a treatment of Rutaceae for the Flora dle Nicaragua and is here described. Amyris oblanceolata A. Pool, sp. nov. TYPE: Nicaragua. Depto. de Estelf: Estelf, elevation 1600 ft., 21 Feb. 1957 (buds and imm. fr), J. B. Salas & B. W Taylor 2267 (holotype, EAP). Frutex vel arbor parva. Folia opposita, trifoliolata, foliolis oblanceolatis vel ellipticis, apice acutis vel rotundatis, retusis, coriaceis. Inflorescentia multiflora, pseudoterminalis, paniculata, ramis pubescentibus, floribus sessilibus. Shrub or small tree, 2-7 m tall, the young branches puberulent. Leaves opposite to subopposite, trifoliolate; leaflets oblanceolate to elliptic, acute to rounded at the apex, with retuse tip, cuneate at base, 5-9 cm long, 2-3.5 cm wide with terminal leaflet larger than laterals, entire, coriaceous, glabrous except midrib puberulent above, with numerous pellucid punctations, the veins reticulate, conspicuous and raised on both surfaces, lateral leaflets sessile or on petiolules to 2 mm, the petiolule of terminal leaflet 4-12 mm; petiole 1.53.5 cm, not winged, puberulent. Inflorescence many-flowered, pseudo-terminal, paniculate, the branches densely puberulent, the flowers sessile in dense clusters, the buds globose; calyx 4-lobed, the lobes triangular, acute at apex; petals 4, glabrous; stamens 7 or 8 in two series, the filaments glabrous; gynophore present; ovary with a few hairs at base. Species of Amyris found in Central America south of Mexico with opposite or subopposite, trifoliolate (or occasionally trifoliolate) leaves are: A. oblanceolata, A. guatemalensis Lundell, members of the A. elemifera species complex, and A. brenesii Standley. Amyris oblanceolata is most similar to A. guatemalensis Lundell, known only from the type, a fruiting collection from Alta Verapaz, Guatemala. Amyris guatemalensis is similar to A. oblanceolata in having subcoriaceous leaflets, an unusual condition in this genus, and short pedicels. Amyris guatemalensis differs from A. oblanceolata in having leaves that are generally 5-foliolate with the lateral leaflets distinctly petiolulate and the tertiary veins neither raised nor conspicuous on the adaxial surface. The leaflets of Amyris guatemalensis are generally elliptic with acuminate apices but sometimes are (like those of the new species) oblanceolate with rounded and retuse apices. Members of the Amyris elemifera species complex (including: A. elemifera L., A. balsamifera L., and A. vestita Lundell) differ from A. oblanceolata in having membranous to chartaceous leaflets and distinctly pedicellate flowers. In addition, their leaflets are generally suborbicular to lanceolate with acute to acuminate apices. The application of names and species circumscription within this group is discussed by Lundell (1960) and Gereau (1991). Amyris brenesii Standley (including A. costaricensis Standley), endemic to Costa Rica, is easily distinguished from other species of Amyris from Central America by its large lateral leaflets, 14-26 cm long, and its long petioles, 9-24 cm long. Paratypes. NICARAGUA. Jinotega: Sierra W of Jinotega, along road to Cerro de la Cruz, elevation 10501350 m, chiefly in dense wet mixed low forest, 27 June 1947 (sterile), P C. Standley 10177 (EAP). Matagalpa: El Eden, camino viejo a Jinotega, 12?58'N, 85058'W, elevation 856 m, 1 Feb. 1984 (buds), P P Moreno 22909 (HNMN, MO). Acknowledgments. I thank W. D. Stevens, Roy Gereau, and Jacquelyn Kallunki for advice and encouragement, and Roy Gereau for assistance in preparing the Latin description.