Platymiscium dimorphandrum Donn.Sm.

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation

Predicted extinction risk: not threatened. Confidence: confident

Klitgaard, B. (2005). Platymiscium (Leguminosae: Dalbergieae): Biogeography Systematics, Morphology, Taxonomy and Uses. Kew Bulletin, 60(3), 321-400. Retrieved from http://www.jstor.org/stable/4111062

Note

The bark slash exudes a yellow-green sap which oxidises red and has a smell of broad beans (Vicia faba). Food bodies on juvenile leaves attract large numbers of ants. The inflorescences are dense, and when in flower the trees make a spectacular show. The flowers are strongly scented, and attract large numbers of bees. The calyces turn blackish- purple, and petals have red venation. Platymiscium dimorphandrum is related to P. yucatanum, which is restricted to the Yucatán Peninsula in Mexico and the adjacent Petén region in Guatemala, and which differs in having solid (vs. hollow) internodes of juvenile branchlets; normally 3- verticillate (vs. normally opposite) leaves; lanceolate or narrowly oblong (vs. broadly triangular) stipules; erect racemes, axis and pedicels hirtellous, (vs. pendulous and glabrous), 6 - 9 mm (vs. 9 - 12 mm long) flowers. Standley 3292, Standley 19302 and Calderon 1013, all sterile and all from El Salvador may represent Platymiscium dimorphandrum. Calzada 1791 is intermediate between P. yucatanum and P. dimorphandrum.

Type

Guatemala. Alta Verapaz: Cubilquitz, March 1902, Türckheim 8199 (lectotype US (US Herb. no. 1337494, from Herbarium of John Donnell Smith); isolectotypes GH, K, M, MO, NY, US from Herbarium of J. Donnell Smith).

Morphology General Habit

Tree to 30 m tall, 75 - 120 cm in diameter; crown spreading to rounded; bark smooth, greenish-grey, shallowly fissured when young, deeply fissured into rectangular blocks (1 x 3 - 4 cm) when older, outer bark 5 mm thick, inner bark 8 - 10 mm thick; slash exudes greenish sap which oxidises dark red; wood very hard, heartwood reddish brown; internodes of juvenile branchlets hollow

Morphology Leaves

Leaves opposite, rarely 3-verticillate, 5 (very rarely 7)-foliolate; vegetative parts glabrous; leaf axis 7 - 10 cm long, including a 4 - 5.5 cm long petiole; stipules triangular to broadly triangular, 5 - 8(- 14) x 5 - 8(- 14) mm, persistent; bud scales and juvenile petiolule bases with food bodies; stipels not observed; leaflets elliptic, distal leaflets larger than others, 2 - 6(- 8) x 1 - 4.5 cm, base rounded, apex acute, veinlets of areoles with sharp edges, usually intermixed with dots, primary vein flush with upper surface, lamina mid green, upper surface glossy, lower dull

Morphology Reproductive morphology Inflorescences

Inflorescences of pendulous, dense, axillary, simple 20 - 50-flowered racemes (occasionally with secondary branching), with 4- 10 inflorescences per axil; inflorescence axis thick, smooth, glabrous, 7- 16 cm long including a 1- 3 cm long peduncle; bract narrowly oblong, 2 - 4 x 0.5 - 1 mm, glabrous, caducous before anthesis; bracteoles narrowly oblong, 2 - 4 x 0.5 -1 mm, glabrous, caducous before anthesis

Morphology Reproductive morphology Flowers

Flower 9 - 12 mm long, compact, pedicellate; pedicels 2 - 4 mm long, slender, glabrate to hirtellous, with sparse food bodies at base articulated from calyx, persisting after flower fall; calyx bell-shaped, 3 - 5 mm long, glabrous, base attenuate, abaxial three teeth triangular, acute, adaxial two fused for 1/2 their length, acute; corolla yellow, petals with red veins; standard orbicular, 7 - 8 x 5 - 7 mm, clawed, yellow marginally, centrally purple; wing petals 7 - 9 x 3 - 6 mm; keel petals 6 - 8 x 3 - 4 mm, adnate along lower margins, glabrous; stamen filaments fused progressively higher abaxially for 1/3 - 1/2 their length, the vexillary stamen only fused at base; anthers dimorphic; ovary long-stipitate, glabrous

Morphology Reproductive morphology Fruits

Samara broadly to narrowly elliptic, 7 - 7.5 x 3 - 3.5 cm; stipe 6 - 10 mm long; exocarp glabrous, rusty brown at maturity; seed 2- 3 x 1.5 cm, oblong-reniform.

Distribution

Widely distributed in southern Mexico, Belize, Guatemala, El Salvador, Honduras, Nicaragua, and Costa Rica.

Ecology

In western Mexico frequent in moist montane forest with Pinus, Quercus and Liquidambar, rare in forests on the Caribbean slopes. In Honduras scattered in tall, deciduous forest with Cedrela, Guazuma, Calicophyllum, Gliricidia, Acacia and Cordia; often near rivers, at 0 - 1100 m, occasionally to 1700 m.

Phenology

Flowering occurs when the trees are leafless or have juvenile leaves, it has been recorded from the end of January to the end of March. Fruit set occurs when trees have mature leaves, about one to two months after flowering.

Conservation

VU A2cd - vulnerable because of a population size reduction of 30% over the last 10 years due to a decline in area of occupancy, extent of occurrence and/or quality of habitat, and due to actual and potential levels of exploitation.

Vernacular

Hormigo, Cachimbo, Palo Hormigo, Sinikte (Mopan Maya) (Guatemala); Hormiguillo, Mulatto, Hormigo (Honduras); Chagane, Sanichte, Shanich Tez (Tzeltal), Hormigueo, Hormiguillo, Palo de marimba, Rosadillo (Mexico); Cortes, Pipa or Chaperno (Nicaragua).

International Legume Database and Information Service

Morphology General Habit

Perennial, Not climbing, Tree