Platymiscium jejunum Klitg.

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

Type

Mexico. Guerrero: Montes de Oca, San Antonio-Monte del Bálsamo, 13 April 1938, Hinton et al. 14001 (holotype K; isotypes G, K, NY, S, US).

Morphology General Habit

Tree to 7 m tall; crown, bark, slash and wood characteristics unknown; internodes of juvenile branchlets solid

Morphology Leaves

Leaves opposite, 5-foliolate; vegetative parts glabrous; leaf axis 7 - 18 cm long, petiole 1/3 - 1/2 as long as rachis; stipules broadly ovate, 3 - 4 x 2 - 3 mm; stipels not seen; juvenile petiolule bases with food bodies; leaflets broadly elliptic to elliptic, distal leaflet larger than others, 10 - 13 x 5 - 7(- 10) cm, base rounded, apex acuminate, veinlets in areoles not observed, primary vein flush with or channelled in the upper surface, lamina mid green, upper surface glossy, lower dull

Morphology Reproductive morphology Inflorescences

Inflorescences of erect, dense, axillary, simple up to 40-flowered racemes, with 1 - 2 racemes per leaf axil or per "short shoot"; inflorescence axis thick, furrowed, glabrous, 4- 7 cm long including an up to 2.5 cm long peduncle; bracts oblong, 2 x 1.5 mm, apex rounded, glabrate to puberulent along margins, caducous before anthesis; bracteoles oblong to obovate, 2 x 1 mm, connate basally, glabrate to puberulent along margins, caducous before flower fall

Morphology Reproductive morphology Flowers

Flowers 5 - 7 mm long, robust, pedicellate to subsessile, spirally arranged or in whorls on inflorescence axes; pedicels 0 - 1 mm long, puberulent to glabrate, with food bodies at base, persistent after flower fall; calyx cup-shaped, 3 - 4 mm long, delicate, puberulent to glabrate, base rounded, abaxial three teeth rounded, adaxial two connate to c. 3/4 their length, obtuse; corolla yellow; standard orbicular or blade wider than long, 6 - 6.5 x 5 - 6 mm, apex emarginate, shortly clawed, claw attenuating; wing petals 5- 6 x 3- 4 mm, wide; keel petals 6 x 2.5- 3 mm, adnate for some part of lower margins, ciliate or glabrous along free part of margins; stamen filaments fused for 1/2 their length, vexillary stamen only fused at base, hairy on inner side of vexillary filament; anthers dimorphic; ovary stipitate, glabrous

Morphology Reproductive morphology Fruits

Samara broadly elliptic to boat- shaped, 7- 11 x 3- 4 cm; exocarp glabrous, rusty- brown, chartaceous.

Distribution

Platymiscium jejunum is recorded from the states of Chiapas, Guerrero, Oaxaca and Vera Cruz in Mexico, and in El Salvador from Parque Nacional Montecristo.

Ecology

Poorly known, at 70 - 1900 m.

Phenology

This species is unusual in bearing mature leaves and inflorescences simultaneously.

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.

Note

Platymiscium jejunum belongs to the group of small-flowered species. It has affinities to P. dimorphandrum and P. yucatanum. From P. dimorphandrum it differs by having solid (vs. hollow) internodes, 5 - 7 mm (vs. 9 - 12 mm) long flowers, 0 - 1 mm (vs. 2 - 4 mm) long pedicels, leaves while flowering (vs. leafless while flowering). From P. yucatanum, it differs in bearing leaves while flowering (vs. leafless while flowering), broadly ovate (vs. oblong to narrowly triangular) stipules, robust, thick inflorescence axes (vs. slender, short ones which curl up during when drying), 0 - 1 mm (vs. 2 - 3 mm) long pedicels, and by having 5 - 7 mm (vs. 6 - 9 mm) long flowers. The derivation of the epithet jejunum is from the Latin word jejunus meaning empty. Here it is used in the sense that P. jejunum lacks good autapomorphies and is rather defined by a suite of characters many of which are found in different combinations in other Platymiscium species.