Virgately erect shrub 6-10 dm, the simple or distally few-branched stems, the ventral face of lf-axes, and the peduncles thinly hirsute with subhorizontal, shining white hairs to ±1-1.5 mm, the loosely imbricate lfts bicolored, lustrous olivaceous above, paler and minutely resin-spotted beneath, the capitula 1—2(—3) together in the axils of 2-3 distal primary lvs and thereafter shortly pseudoracemose; phyllotaxy distichous. Stipules erect, ovate from shallowly cordate base, ±6-10 x 3.5-7 mm, palmately 11-21- nerved from point of attachment, tardily deciduous. Lf-formula (i—)ii/32—39; lf-stks 1—3(—3.5) cm, the petiole 6-22 mm, the one interpinnal segment 6-20 mm; pinnae equilong or the distal pair a little longer, the rachis of these ±8-11(-13) cm, the longer interfoliolar segments 24.5 mm; lft-pulvinules 0.3-0.7 x 1 mm; lfts little graduated, narrowly oblong-elliptic from shortly obtusely auriculate base, obtuse, the longer ones 10-13.5 x 2.7--4.7 mm, 2.7--4.7 times as long as wide; venation palmate, the midrib displaced to divide blade ±1:2, the inner posterior primary nerve incurved-ascending far beyond mid-blade, the secondary venules ascending at narrow angles, randomly anastomosing, the whole blade when young appearing subvertically striate, the venation nearly immersed in age. Peduncles 2.5-5.5 cm, ebracteate; capitula 5-9-fld, the receptacle 2-3 x 3--4.5 mm, but sometimes one fl displaced onto peduncle; bracts ovate or lance-ovate 3-6.5 mm, early dry deciduous; fls subsessile homomorphic, the broad solid pedicel ±0.7 x 1.4-2.4 mm; perianth "yellow, shiny, ± sticky," the calyx 4-, the corolla 3--4-merous, both glabrous in lower half, thinly white-pilose distally, the calyx-lobes striately subparallel-nerved, the corolla only faintly so; calyx 5.5-7 mm, the lanceolate teeth 3.4-5 mm; corolla ±8.5-10 mm, the ovate lobes ±3 mm; androecium (of 2 fls examined) 86-96-merous, 28-32 mm, the thickened stemonozone 1.7-2 mm, the tube 8-10 mm, the tassel white; no intrastaminal disc; ovary at anthesis glabrous. Pods (few seen) ±10 x 1.1 cm, the dilated sutural ribs in dorsal view 2+ mm wide, the plane recessed valves reticulately venulose, resinously papillate, and together with the margins densely softly pilose overall; seeds unknown.

In campo rupestre, on granite bedrock, ±1000 m, known only from the type-locality near 12°30'S in Sa. do Sincorá, upland interior Bahia, Brazil. — Fl. XII-I, VI; fr. V-VI(-?).

Calliandra paterna, now known from four collections from Morro do Pai Inacio (whence the epithet), is compared in the diagnosis to C. renvoizeana which also has only one or two pairs of pinnae per leaf, but differs in leaflets about twice as many, scarcely half as large, and weakly one-nerved. The also related C. debilis may be recognized by its smaller calyx (±4, not 5.5-7 mm) and glabrous corolla.