Arborescent shrubs, fertile when 0.8-10 m, with terete, densely foliate gray- or fuscous-pilosulous or sometimes sordidly pilose long-shoots but lacking brachyblasts, the lvs strongly discolorous, the contiguous or narrowly imbricate lfts stiffly chartaceous, on upper face dark olivaceous (brown when dry) and highly lustrous, paler dull beneath, either glabrous facially and thinly ciliolate or on dorsal face thinly finely strigulose or (very locally) loosely pilose, the capitula of ± silvery-pilosulous, red-stamened fls borne singly or in fascicles of 2-3 in the axil of distal, coevally expanding lvs or, by suppression of these, shortly pseudoracemose; phyllotaxy distichous. Stipules firm, linear-lanceolate or narrowly ovate (2-)2.5-10.5 x (0.6-)0.8-3 mm, caducous. Lf-formula (in uppermost lvs i—)ii—viii/21—52; lf-stk of major lvs below inflorescence 1-6 cm, the petiole (consisting largely of pulvinus) 3-7 x 0.9-2.3 mm, the longer interpinnal segments 4-13 mm, the shallow ventral groove weakly bridged; pinnae (when >1 pair) scarcely or distinctly accrescent distally, the rachis of longer ones 4-8(-9) cm, the longer interfoliolar segments 0.9-1.6 mm, the lfts widely ascending, forming when spread a lf-blade of narrowly elliptic or oblance-elliptic outline; lft-pulvinules 0.1-0.25 x 0.6-0.9 mm; lfts abruptly decrescent near top of rachis, more gradually so toward its base, the blades linear from postically angulate base, obtuse, straight or almost so, those near mid-rachis 6-12 x 1.1-2.5 mm, 4.6-6.7 times as long as wide; venation palmate, the simple midrib displaced to divide blade ±1:2-3, the inner posterior and in broader blades one anterior primary nerve ascending parallel to midrib almost or quite to blade’s apex, the 2-3(4) outer posterior primaries progressively much shorter, the venation weakly prominulous or immersed on upper face, slenderly prominulous beneath. Peduncles 9-26 mm, either ebracteate or charged just below the capitulum with 1 small bract; capitula 5-12-fld, the fls homomorphic, the receptacle clavate or hemispherical 1.8-2.5 mm diam; floral bracts 0.8-1.8 mm, caducous; perianth usually 4- rarely 5-merous or the calyx randomly 3-merous; pedicels cryptic, 0.2-0.5 x 0.45-0.9 mm; calyx campanulate (1.5-)1.6-3.2(-4) mm, usually only thinly puberulent, brown, nerveless or faintly 5-15-nerved, the deltate or triangular teeth 0.3-1.2 mm; corolla 5.2-8.2(-9.5) mm, always silvery-pilose, rarely densely so and barbate, the lobes 2.4—3.8 mm; androecium 12-20(-25)-, in one population to 40-merous, 27-50 mm, the stemonozone 1-3 mm, the tube 1.8—3.8(—7) mm, the tassel red. Pods in profile 5-9 x 0.95-1.15 cm, the dilated sutural ribs 2.5-3.5 mm wide in dorsal view, the recessed valves densely brown-papillate and thinly pallid-pilosulous, not externally venulose; seeds (scarcely known) ±7 mm in long diam, the close-fitting testa olivaceous, smooth, with well-defined pleurogram.

About rock outcrops in savanna, on and near tepuis of Venezuelan Guayana and adjoining Brazil, most common on table-mountain tops at 1100-1500 m but occurring also along rocky banks in the foothills at 100-150 m, represented by variously modified types in different parts of a discontinuous range, described below in more exact detail. — Map 46. — Fl. I-VI, very likely at other times.

In the small Guayanan series of calliandras characterized by parallel primary nervation of leaflets the polymorphic C. tsugoides is recognized by number and size of ventrally glossy leaflets and by lack of granular trichomes; for details see Key III. Its known populations are ecologically restricted and mutually distant in dispersal, and differ one from the next in leaf-formula, pubescence, proportions of calyx to corolla, and filament-number. The intraspecific variation is analysed in the key that follows, but seems too weak to support the recognition of formal taxa.