Shrubs, erect, to 3 m; bark dark gray, smooth. Stems not flexuous, glabrous or sparsely pubescent, hairs appressed, not glutinous; short shoots present. Leaves 4.8–17.5 mm; stipular spines terete, slightly recurved, 4–15(–22) × 0.6–0.9 mm near base; petiole 4–10 mm, sparsely puberulent, hairs appressed; petiolar gland 1, just below lowermost pinnae, sessile, circular, 0.1–0.4 mm diam., donut-shaped; rachis 0–8 mm; pinnae 1(or 2) pairs, 9–25 mm; leaflets 6–14 pairs per pinna, blades subterete, linear, 2.8–6.1 × 0.3–0.6 mm, base cuneate, apex acute, surfaces glabrous. Peduncles 20–28 mm. Inflorescences globose heads, densely flowered, 5.5–7.5 mm diam., solitary or clusters of 2–5 on short shoots; involucre near middle of peduncle. Flowers pale yellow; calyx 0.8–1.2 mm, glabrous or sparsely puberulent; corolla 1.8–2.2 mm, glabrous; filaments yellow, 3–4 mm. Legumes linear, flattened, 40–90 × 5.5–7.8 mm, sometimes constricted between seeds. Seeds uniseriate.

Phenology: Flowering Apr–Aug.
Habitat: Washes, on slopes in open thorn scrub.
Elevation: 800–1200 m.

Distribution

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Discussion

Within its very restricted range, Vachellia schottii is a common species, often occurring in large, relatively pure thickets over extensive areas, apparently being quite successful within this small area. These areas of thorn scrub are located on limestone or gypsum derived soils. Vachellia schottii is known only from the Big Bend region in Brewster and Presidio counties. This species probably occurs to the south in adjacent Mexico, though the authors have seen no specimens from that region.

Selected References

None.

Lower Taxa

None.