Shrubs or trees, unarmed, 1–6 m. Stems bark greenish gray, smooth, with raised orange-brown or pale gray lenticels in semaphore lines, inner bark green, glabrous or pubescent. Leaves: stipules early caducous, ovate, 15 mm, base cordate-auriculate proximal to point of attachment, apex acute to rounded, surface glabrous, margins ciliate and glandular; petiole 2–8 cm, glabrous or pubescent, eglandular; rachis 4–12 cm, glabrous or pubescent, eglandular; pinnae 2–4(or 5) pairs, opposite, also with terminal pinna; leaflets in (2 or)3–5(or 6) opposite pairs, petiolulate, blades obovate-elliptic, median 10–28 × 7–18 mm, terminal 11–35 × 7–18 mm, base inequilateral, margins revolute, slightly thickened, apex obtuse, rounded, truncate or shallowly emarginated, main vein prominent abaxially, secon­­dary veins brochidodromous, surfaces glabrous or moder­ately pubescent, or abaxially with small tuft of hairs in main vein axis; blades eglandular but with gland-tipped, cone-shaped appendages, clustered into a corona at pinnae insertions and a single gland-tipped appendage proximal to each leaflet pulvinule, these evident on very young foliage. Inflorescences 20–30+-flowered, axillary or terminal, compact or long and lax, erect, 4–30 cm; axis, pedicels, and calyces moderately pubescent or glabrous, eglandular; bracts early caducous, ovate, concave, 0.5–2 mm, glabrous with ciliate margins. Pedicels articulate 2–7 mm proximal to calyx, 13–30 mm, when pubescent, hairs densest at point of articulation. Flowers: calyx base tapering into distal section of pedicel, lobes 6–9 mm, lower lobe cucullate in bud, imbricate in anthesis, inner surface densely pubescent; petals clawed, blade base and claw pubes­cent; banner spotted or faintly streaked orange-red at base, obovate to cordate, 10–12 × 8–10 mm (including 1–1.5 mm claw), apex emarginate, abaxially stipitate-glandular with yellow or orangish glands on proximal 1/2, blade base and claw pubescent, claw margins stipitate-glandular, inner surface of claw without appendage or thickened ridge; upper laterals obovate-suborbiculate to cordate, 12–14 × 9–10 mm (including 1.5–2 mm claw), apex emarginate, base of blade and claw glandular abaxially, claw sparsely pubescent inside; lower lat­erals obovate-elliptic to cordate, apex emarginate; fil­aments 12–13 mm, pubescent on basal 1/2–3/4; anthers 2 × 0.8 mm; ovary pubescent and eglandular or densely glandular; style curved, 10 mm, pubescent; stigma a terminal, fringed, tubular or funnel-shaped chamber. Legumes 4.4–7.5 × 1.4–2 cm (including a 1.5 mm beak), subligneous, glabrous or moderately to sparsely glandular with sessile or short-stalked glands. Seeds (1 or)2–5, orbicular or cordate, 9–10 × 7.5–8.5 mm, shiny.

Phenology: Flowering Jan–Nov.
Habitat: Low, deciduous forests, open semiarid scrub.
Elevation: 10–150 m.

Distribution

• Generated Map
• Legacy Map

Tex., Mexico (Baja California, Chihuahua, Hidalgo, Jalisco, Nayarit, Nuevo León, Querétaro, San Luis Potosí, Tamaulipas, Veracruz).

Discussion

Erythrostemon mexicanus is cultivated as an ornamental in tropical and subtropical climates. The native range extends into extreme southern Texas as far northward as Webb County.

Selected References

None.

Lower Taxa

None.