识别要点：Similar to Senegalia kunmingensis in having sessile leaflets (resulting from the squat petiolule that does not extend below the base of the leaflets) and long-pedunculate heads that occur within the upper leaf axils and in elongated, terminal racemes, but differs in having shorter petioles (8–25 mm), more numerous pinnae (13–17 pairs) with more numerous and smaller leaflets (normally 45–60 pairs and 5–7 × 1–1.8 mm), compared to petiole 40–80 mm long, pinnae 3–9 pairs, leaflets normally 21–33 pairs and 6–13 × 1.5–3 mm in S. kunmingensis; also, while the main vein of the leaflets in both species starts from near the upper margin, in S. propinqua it is close to and parallel with the upper margin, while in S. kunmingensis it runs obliquely to the leaflet apex; furthermore, S. propinqua is a non- lianescent shrub, while S. kunmingensis is commonly a liana or lianescent shrub.
形态特征：Erect, openly and rather sparingly branched, non-lianescent shrubs 2–5 m tall, single- or more commonly several-stemmed from ground level, the primary branches ascending to erect (sometimes almost contiguous with main stem); bark on stems and mature branches grey to dark grey or sometimes brown; lenticels numerous, prominent and circular or oblong to linear (transversely orientated). New shoot at first enclosed within a conspicuous bud comprising up to ten, spirally arranged and imbricate scales, the scales coriaceous, longitudinally striate, brown or dark purple and densely short-hairy; when fully emerged the sterile branchlets often short (3–5 cm long), with 3–5(–6) densely arranged leaves, yellowish green and with dense, short, patent or curved hairs but glabrous or occasionally sparsely hairy with age; fertile branches usually longer (to 50 cm) and with up to 7, widely spaced leaves. Prickles internodal, scattered on mature branches, very few or absent on young branchlets, normally absent from leaves (rarely present on lower surface of rachis), often not seen on herbarium material, c. 1 mm long on branchlets but to c. 5 mm long on branches, straight or shallowly recurved. Stipules caducous, narrowly obovate to spathulate, 3–6 × 0.5–2 mm, densely hairy and obscurely veined abaxially or veins not visible, not lobed at base, apex acute to acuminate. Leaves bipinnate; pinnae (10–) 13–17 pairs, 7–12 mm apart (to 20 mm in regrowth plants), 40–60 (–85) mm long on medial pairs, sometimes to 15 mm long on lowermost pair; petiole (including the prominent pulvinus) 8–25 mm long on mature branches, to 36 mm in regrowth plants; rachis 110–180 mm long, densely short-hairy, the hairs curved. Leaflets 45–60 pairs on medial pinnae, to 25 pairs on lowermost pinnae, narrowly oblong, 5–7 mm long, 1–1.8 mm wide, thick, flat, close together (sometimes slightly imbricate), straight or more commonly shallowly curved towards apex of pinna rachis, dark green above and paler green below, glabrous on the upper surface, sparsely appressed hairy on margins and lower surface (densest on main vein), the hairs on basal angle sometimes spreading; apex asymmetric, rounded to obtuse or sometimes broadly acute, sometimes with an apiculum; base truncate, unequal with a square angle on lower edge, the petiolule squat (not extended below base of leaflet) and clearly eccentric; main vein starting very close to upper margin at leaflet base, then close to and parallel with upper margin for most of leaflet length, normally slightly curved away from margin at leaflet apex; lateral veins (on lower surface of leaflets) ±evident, patent or sub-patent, often bifurcating near margin, tertiary veins inconspicuous but appear to form an indistinct and imperfect reticulum (observe dry specimens). Glands: petiole gland– position varies from distal end of pulvinus to immediately below first pair of pinnae, sessile, oblong to obovate or elliptic or sometimes circular in plane view, normally symmetrically thickened but sometimes slightly raised at distal end, 1.2–3 (–4) mm long, 1.2–1.5 mm wide, raised to c. 0.5–1 mm high, slightly concave or longitudinally grooved in the center (rarely flat-topped or, on young leaves, domed), pale green or yellowish green and smooth or more commonly wrinkled when fresh, often wrinkled when dry; rachis glands—situated at base of uppermost 1 (rarely 2) pairs of pinnae, sessile, circular, c. 1 mm diam., slightly raised, concave above; rachilla glands—situated at base of the distal pair of leaflets (often obscured by the leaflet bases), or more often absent, minute, sessile, black. inflorescences comprising 1–3 pedunculate heads within upper leaf axils and also arranged in elongated, terminal racemes with young leaves or leaf primordia at base of peduncles during anthesis, indumentum on raceme axes comprising short, dense, straight-patent or curved-appressed white hairs (difficult to see in fresh material), also with a dense layer of dark reddish brown glandular hairs in narrow grooves at apex of some raceme axes; peduncles 15–30 mm long, indumentum similar to raceme axes except glandular hairs relatively few and scattered uniformly on some peduncles; peduncular bracts early caducous, often two, situated close to base of heads, filiform, 2–4 mm long, heads globose or oblongoid, 14–17 mm diam. at anthesis when fresh (c. 14 mm when dry), white to cream-coloured (dirty yellow as stamens wither), c. 40-flowered, the flowers densely arranged in the heads (best observed in mature buds); inflorescence buds pale green but aging cream-coloured when fresh, pale yellowish or pale brown when dry. Bracteoles narrowly spathulate, to 2 mm long, laminae less than 0.5 mm wide, often brown and slightly exserted beyond flowers in buds. Flowers 5-merous, sessile or with very short pedicel (0.5 mm long); calyx c. 2 mm long, 3⁄4–7⁄8 length of petals, gamosepalous, dissected for 1/3–1/2 into triangular or oblong-acute or -obtuse lobes that are cream-coloured when fresh, calyx tube densely hirsutellous (observe at x10 mag.) and 5-veined (veins obscure to visible but not especially prominent); petals 2.5–4 mm long, cream-coloured when fresh, with dense short hairs; stamens very numerous, free to base or a few loosely cohesive at extreme base, exceeding petals by about same length as petals. Ovary densely long hirsute. Pods and seeds unknown.
