Senegalia petrensis (Thulin) Kyal. & Boatwr.

M. Thulin et al. Flora of Somalia Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Type

N2, 34 km from Ceerigaabo along road to Mayd, just below Madar mage, Thulin 11000 (UPS holo., K iso.)

Morphology General Habit

Slender tree, 2–4 m tall, with somewhat flattened to ± rounded crown; bark yellowish-brown, peeling in papery flakes; young branchlets appressed puberulous, purplish- to greyish-brown, angular, soon becoming glabrous

Morphology Leaves Stipules

Stipules not spinescent, quickly falling

Morphology General Prickles

Prickles in threes, spreading and usually somewhat curved downwards, dark grey to black, glabrous or sparsely puberulous when young, the middle one up to 6 mm long, the lateral ones up to 5.5 mm long, or occasionally prickles solitary

Morphology Leaves

Petiole up to 2 mm long, puberulous, eglandular; pinnae 1–2 pairs with a circular gland c. 0.3–0.4 mm in diam. between the pinnae of the lower pair and often also a slightly smaller gland between the pinnae of the upper pair

Morphology Leaves Leaflets

Leaflets (6–)8–10(–12) pairs per pinna, 2–4.5 x 0.5–1.5 mm, ± narrowly oblong, slightly oblique at the base, obtuse to subacute at the apex, sparsely puberulous along margins and on lower surface or glabrous, without or sometimes with few visible lateral veins

Morphology Reproductive morphology Inflorescences

Inflorescences spicate; axis 15–35 mm long including up to 7 mm long peduncle, puberulous to subglabrous

Morphology Reproductive morphology Flowers

Flowers (seen in dried up state or in bud only) sessile, probably white

Morphology Reproductive morphology Flowers Calyx

Calyx c. 1.5 mm long, whitish, ± deeply and irregularly lobed, glabrous

Morphology Reproductive morphology Flowers Corolla

Corolla c. 2.5 mm long, glabrous

Morphology Reproductive morphology Fruits

Pods straight, oblong, compressed, dehiscent, brown, 25–50 x 10–13 mm, narrowing to a 3–7 mm long stipe at the base, ± pointed at the apex, 1–4-seeded, sparsely puberulous throughout, with a distinct reticulate venation

Morphology Reproductive morphology Seeds

Seeds (no quite ripe ones seen) compressed, subcircular, c. 5 mm in diam.; areole subcentral, c. 1 x 1.5 mm, open.

Distribution

N2 not known elsewhere.

Ecology

Altitude range 850–1200 m.

Vernacular

Xobobloho (Somali)

Note

The prickles in threes or solitary, the leaves with eglandular petiole and glands present in the junction between the pinnae only, and the yellowish-brown peeling bark indicate a relationship with A. ochracea in southern Somalia and A. mahrana in eastern Yemen. From A. ochracea it differs in the almost straight (not hooked) prickles, flowers with a whitish (not reddish) calyx, and pods with a more or less pointed (not rounded) apex. From A. mahrana it differs mainly in its (6–)8–10(–12) (not 3–6) pairs of leaflets per pinna and in its pods that are puberulous throughout (not at base and margins only) and have a distinct reticulate (not weak and transverse) venation.