Myroxylon balsamum (L.) Harms

  • Authority

    Isely, Duane. 1981. Leguminosae of the United States. III. Subfamily Papilionoideae: tribes Sophoreae, Podalyrieae, Loteae. Mem. New York Bot. Gard. 25 (3): 1-264.

  • Family

    Fabaceae

  • Scientific Name

    Myroxylon balsamum (L.) Harms

  • Description

    Species Description - Large tree to 40 m in native habitat; bark resinous and aromatic when broken. Leafstalk 5-10(-15) cm; leaflets (5-)7-13, alternate or irregular, petiolulate 2-4 mm, ovate or elliptic-oblong, acuminate, 3-8(-12) cm, 1.7-3 r, coriaceous, glossy, glabrous, reticulate, with pellucid lines and dots. Inflorescences axillary or terminal, congested, with glandular-puberulent axes. Flowers numerous, 7-9 mm (-slightly larger), soon divergent or nodding. Pedicels 4-8 mm. Calyx broadly bowl-shaped, 4-6 mm, irregularly undulate or abortively-toothed, finely canescent-puberulent. Corolla inconspicuous, white; standard ca. 10 mm, ascending or curved, broadly ovate, long-clawed. Stamens exserted, with conspicuous anthers. Pistil glabrous; ovary narrowly obovate, with 2 subterminal ovules. Legume exserted-stipitate 5-10 mm, oblong-oblanceolate, distally rounded, flat except at seed-bearing apex, 5-11 cm x ca. 2-2.5 cm, punctate or not; valves (central portion) linear-oblanceolate, coriaceous, longitudinally striate and becoming wrinkled, expressed over the apical seed; wings papery, smooth, constituting most of the width of the fruit. Seed 1, 1-2 cm.

  • Discussion

    The Peru-balsam, an economic species of the tropics, is recognized by its irregularly alternate leaflets, small, nodding flowers (little bowls with a central cluster of shortly exserted anthers), and fruits resembling a giant maple samara. There are two varieties, once considered species, distinguished principally by different range and properties of the balsam. The morphological and geographic differences attributed to these taxa by Rudd (1968a, 1972) are: 1. Fruits ca. 8-11 cm, with nearly parallel margins; leaflets the larger, glabrous, acuminate, or sometimes acute; “Panama, Columbia, Venezuela, perhaps elsewhere.” var balsamum. 1. Fruits 6-9 mm, usually narrowed to the base; leaflets smaller, sometimes puberulent along mid vein, usually acute-tipped; “southern Mexico to Panama (and Colombia?). Introduced elsewhere.” var pereirae. Rudd (1968a), however, acknowledged that varietal identification of specimens is difficult, “the most important differences . . . seem to be in the physical and chemical properties of the balsam ... I am citing all Mexican collections as var pereirae . . . because many of the herbarium vouchers are sterile . . . .“ Among specimens I have examined, leaf shape and range attributed to the varieties do not satisfactorily correlate. I have not seen enough fruiting material for evaluation. The most discrete feature usually seems to be leaflet size, the larger ones of the South American plants usually being 8-9 cm, those of Mexico and Central America 4-7 cm.

  • Distribution

    Subtropical Florida. Native of Mexico to n South America; cult in tropics of both hemispheres. Introduced, botanical gardens and U.S.D.A. plantings. Balsam of Peru.

    United States of America North America| Mexico North America| Central America| Colombia South America| Venezuela South America| Guyana South America| Suriname South America| French Guiana South America| Brazil South America|