Abarema campestris

Title

Abarema campestris

Authors

Rupert C. Barneby

Scientific Name

Abarema campestris (Spruce ex Benth.) Barneby & J.W.Grimes

Description

20. Abarema campestris (Bentham) Barneby & Grimes, comb. nov. Pithecolobium campestre Spruce ex Bentham, Trans. Linn. Soc. London 30: 583. 1875 & in Martius, Fl. Bras. 15(2): 436. 1876. —"Habitat in campis altis Santarem, provincia Para: Spruce n. 771." — Holotypus, K(herb. bentham.)! = NY Neg. 2007; isotypi (some lacking collector's serial number), †B = F Neg. 1183!, BM!, G!, GH!, NY!, P (3 sheets)!.

Pithecolobium campestre sensu Ducke, 1949: 36.

Macrophyllidious shrubs and treelets 1-4.5 m with reddish gray scaley bark, the stems, lvs, and peduncles when very young densely puberulent with appressed-ascending or spreading-incurved, pallid or rufous hairs to ±0.1-0.25 mm but all the peduncles, early glabrate, the stiffly papery lfts glabrous when fully expanded, dull olivaceous above, paler beneath, the dense capitula of red white-stamened fls solitary or 2-3 together in a few distal lf-axils, immersed in foliage. Stipules linear-lanceolate 1.5-4.5 mm, caducous. Lf-formula (i—)ii—iii/3—5; lf-stks (3-)7-23 cm, the petiole including dilated lurid pulvinus 2.5-7.5 cm, at middle 1.3-2.8 mm diam, the longer interpinnal segments (2-)2.5-8.5 cm; first nectary contiguous to or close to pulvinus, randomly differentiated, either immersed or mounded, often longer than wide, 1.25— 4.3mm in greatest diameter, similar but smaller nectaries often at insertion of pinnae (but sometimes lacking) and yet smaller ones at tip of some pinna- rachises; pinnae strongly accrescent distally, the rachis of furthest pair ±4—19 cm, the longer interfoliolar segments (1.2-) 1.5-5 cm; pulvinules 2-5 x 0.7-1.2 mm, livid and wrinkled; lfts accrescent distally, often much so, ovate, lanceolate, elliptic-lanceolate or rarely elliptic from subequilateral, rounded or subcordate base, shortly obtusely acuminate, the distal ones 3.4-9(-12) x (2-)2.3-4.2(-5) cm, 1.8-2.6 times as long as wide; the straight, almost centric midrib giving rise on each side to 9-14 major (and numerous intercalary minor), widely divergent secondary nerves brochidodrome well within the plane margin, these randomly few-branched to form an open reticulum, the whole venation immersed on upper face, prominent beneath. Peduncles 2-6.5 cm; capitula 15—35-fld, the receptacle becoming 2-6 mm; lower bracts ovate-triangular, the upper spatulate, none over 2 mm, all deciduous but the lowest less readily than the rest; fls all sessile or some lower ones contracted at base into a pedicel to 1(—1.5) mm, ordinarily dimorphic, with one or several differentiated fls at apex of spike, but sometimes almost uniform; perianth 5(-6)-merous, the obtusely 5-angulate calyx and the corolla-lobes densely brown-puberulent, but the corolla-tube more thinly so or glabrate; PERIPHERAL FLS: calyx conic-campanu-late (2.5-)3-4.5 mm, the low-deltate obtuse teeth 0.3-0.7 mm; corolla tubular-campanulate (6.5-)7-8.5 mm, the lance-ovate lobes 1.7-2.7 mm; androecium (28-)36-46-merous; ovary symmetrically conical at tip, glabrous; stigma poriform; TERMINAL FL(S): calyx 3-4.5 mm; corolla 9-10 mm; stemonozone sometimes to 4 mm, the filament tube 10-13 mm. Pods mostly solitary, in profile broad-linear from attenuate base, when well fertilized 10-18 x 1.5-2.4 cm, incurved through a full circle or further, 8-12-seeded, the stiffly papery glabrous, coarsely venulose valves low-convex over each seed, dull fuscous externally, red-orange within, framed by scarcely constricted plane sutures 1.6-2.5 mm wide; dehiscence elastic through the length of both sutures, the valves recurved and coiling; seeds plumply ellipsoid ±7.5—9 x 5.5-7 mm in broad view, bicolored, the testa in lower half firm and white, translucent distally and transmitting the blue color of the embryo, the pleurogram finely engraved on both faces.

In campo thickets on terra firme and in brush-woodland on hills, thriving in capoeira, mostly on sandy soils at ±100-150 m, local in Amazonian Brazil on S affluents of the great river; in E Amazonas (Maués) and W Pará (Ríos Arapiuns and lower Tapajóz), extending S in the Madeira and Tapajóz basins to ±6°30'S on Río Maicoré and 8°S on Río Cururú.— Map 22. — Fl. IX—II.

Abarema campestris is sometimes mistaken for the related and partly sympatric A. cochleata, which is similar in equilateral outline of the leaflets. From this it differs decisively in the longer primary leaf-stalks and disproportionately short secondary leaf-axes, which give the whole leaf a characteristic outline, and in the pale green, nearly concolorous leaflets.