Calliandra Bentham, Hooker, J. Bot. (Hooker) 2: 138. 1840, nom. conserv. — Sp. typica (Hernandez & Nicolson, Taxon 35: 747-748. 1986): C. houstoniana (Miller) Standley.

Anneslia Salisbury, Parad. Lond. 64: 1807, nom. rejic. — Sp. unica: A.falcifolia Salisbury, nom. illegit. = Calliandra houstoni (L’Heritier) Bentham = C. houstoniana (Miller) Standley.

Clelia Casaretto, Nov. Stirp. Bras. 83. 1845. — Sp. unica: Clelia ornata Casaretto = Calliandra harrisii (Lindley) Bentham.

Codonandra Karsten, Fl. columb. 2: 43. 1862. — Sp. unica: Codonandra purpurea Karsten = Calliandra codonandra Bentham = Calliandra magdalenae (de Candolle) Bentham var. magdalenae.

Calliandra sensu Bentham, Trans. Linn. Soc. London 30: 526-557, exclus. ser. Laetevirentibus, quae = genus Zapoteca Hernandez, necnon spp. paucis paleotropicis.

Trees, shrubs, and subshrubs, some functionally herbaceous from perennial root-stock or rhizome, none monocarpic; phyllotaxy distichous or exceptionally spiral. Indumentum of simple, white, sordid or brown-black hairs often mixed with short, amorphously pluricellular, usually red or brown, herein termed granular trichomes, and in very few spp. with gland-tipped or stellately branched hairs, exceptionally lacking or almost so. Stipules herbaceous or sub- coriaceous, commonly striately venulose dorsally and either deciduous or persistent, exceptionally dilated, or papery, or spinescent. Leaves bipinnate or (C. hymenaeodes) simply pinnate; petiolar nectaries 0; lf- formula diverse and often intraspecifically unstable, i-many/l-many, the number and size often reciprocally adjusted; venation of lfts either palmate from the pulvinule or palmate-pinnate, or in small lfts reduced to simple midrib. Inflorescence composed of capitula, or condensed racemes, or umbels, arising either from contemporary lf-axils or more commonly from axillary brachyblasts, or forming through suppression of distal lvs a terminal psuedoraceme, exceptionally (C. brevicaulis) consisting of a solitary, truly terminal umbel; peduncles either bracteate or not; bracts subtending each fl ordinarily persistent through anthesis; fls of each unit of inflorescence either homomorphic, or heteromorphic in shape and the terminal one(s) in some respect larger, and/or the peripheral ones staminate and the distal one(s) bisexual, or the enlarged terminal fl staminate; perianth normally in most spp. 5-merous, but occasionally 3-, 4-, or 6-merous, or randomly irregular, the outer fls of densely compact capitula often asymmetric or incurved, the calyx and corolla often striately veined; androecium (7-)10(-poly)-merous, the filaments united into a tube ±1/3 to twice or more the length of the corolla, the stemonozone either obscure or forming a well-differentiated hypanthium; intrastaminal nectaries either present or 0, the inner face of hypanthium then nectariferous; anthers dorsifixed, transversely oblong to elliptic; pollen shed in 8-grained ± pyriform polyads, the basal grain narrowed proximally, sticky; ovary sessile or almost so, tapering into the style, the stigma dilated but sometimes scarcely so, the stigmatic surface either convex, or shallowly cupular, or obscurely penicellate; ovules often 8, sometimes fewer, rarely to 11. Pods either erect- ascending on thickened peduncle or plagio- to geotropic, in profile narrowly oblanceolate or linear- oblanceolate, straight or slightly falcate, the plane or low-convex, stiffly coriaceous or ligneous valves recessed into a frame formed by the thickened, sometimes massive sutural ribs; dehiscence elastic, from apex downward or from both ends, the valves recurving but not laterally twisted; seeds descending on short dilated funicle, plumply discoid or compressed- ovoid or -rhomboid, the testa hard, the pleurogram either U-shaped or lacking.

An American genus (see discussion above) of ±135 spp., ranging from s.-w. United States to Uruguay, warm-temperate Argentina, and n. Chile, most plentiful and diverse in monsoon climates and in open brush- woodland or savanna communities at low and moderate elevations, many in riparian forest, a few Hylaean, some tropical submontane, several adapted to desert.