Herbs or shrubs, annual or perennial (usually deciduous, evergreen in Peritoma arborea); spines usually absent (present in Hemiscola and Tarenaya); glabrous or glandular-pubescent, hairs stalked or sessile (producing glucosinolates). Stems usually erect, sometimes spreading or procumbent; branched or unbranched. Leaves alternate, spirally arranged (usually palmately compound, sometimes simple); venation pinnate; stipules usually present (usually caducous, sometimes deciduous, 3-8-palmatifid, linear, threadlike, minute, scalelike, or absent, nodal (stipular) spines present in Tarenaya and Hemiscola); petiole present (pulvinus usually present, nectaries absent, petiolar spines sometimes present, petiolules present); blade margins entire, serrate, or serrulate. Inflorescences terminal or axillary, usually racemose, sometimes flat-topped, or flowers solitary (usually elongated in fruit); bud scales absent; bracts present or absent (unifoliate, often trifoliate proximally, bracteoles absent). Pedicels present. Flowers usually bisexual (developmentally unisexual within sections of racemes), actinomorphic or slightly zygomorphic, rotate to crateriform, campanulate, or urceolate; perianth and androecium hypogynous; sepals persistent or deciduous, 4, distinct or connate basally; petals 4, attached directly to receptacle, imbricate, distinct, equal or unequal; intrastaminal nectary-discs, scales, or glands present or absent; stamens [4-]6-27[-35]; filaments free or basally adnate to gynophore (or along proximal 1/3-1/2 in Gynandropsis) or androgynophore, glabrous or pubescent; anthers dehiscing by longitudinal slits, pollen shed in single grains, binucleate, commonly tricolporate; gynophore present or absent; pistil 1; ovary 1-carpellate (except 2 in Oxystylis), 2-locular; placentation parietal; ovules 1-18(-26+) per locule, anatropous, bitegmic; style 1 (straight, relatively short, thick, not spinelike in fruit, except in Oxystylis, sometimes in Wislizenia); stigma 1, capitate, unlobed. Fruits capsular or nutlets (usually stipitate from elongation of gynophore, erect to divergent, usually not inflated), valvate, elongate (± dehiscent by 2 lateral valves, except in Polanisia), or schizocarps (inflated in Peritoma arborea), indehiscent or dehiscent. Seeds 1-65[-200], tan, yellowish brown, light brown, pale green, brown, reddish brown, silver-gray, or gray to black (papillose or tuberculate); arillate or not; endosperm scanty or absent, persistent perisperm sometimes present; cotyledons incumbent, (radicle-hypocotyl elongated).
Herbs [rarely shrubs], sometimes woody at base, producing mustard oils. Stems erect, sparsely or profusely branched, glabrous or glandular pubescent. Stipules scalelike or absent, caducous (petiolar spines sometimes present). Leaves alternate, spirally arranged, palmately compound; petiole often pulvinate; leaflets [1 or]3-7[-11]; leaflet blades with pinnate venation. Inflorescences racemes or corymbs or flowers solitary and axillary; peduncle present; bract present [or absent] at base of pedicels. Pedicel present; bracteoles absent. Flowers bisexual but sometimes appearing unisexual due to incomplete development, actinomorphic or slightly zygomorphic, rotate, crateriform, campanulate, or urceolate, hypogynous. Sepals 4, distinct or basally connate, persistent. Petals 4, distinct, imbricate, attached directly to receptacle; intrastaminal nectary-disk or glands present or sometimes absent. Stamens 6(-32); filaments free or basally adnate to gynophore (or along basal 1/3-1/2 in Gynandropsis); anthers dehiscing by longitudinal slits; pollen shed in single grains, 2-nucleate, commonly 3-colporate. Pistil 1, 2-carpellate; ovary superior; ovules 1 to many per locule, 2-tegmic, anatropous, placentation parietal; style 1, straight, short, thick; stigma 1, capitate, unlobed. Fruit an elongate capsule, ± dehiscent by lateral valves along their entire length [indehiscent or dehiscent schizocarp], usually stipitate from elongation of gynophore (lacking in Arivela). Seeds 1-10(-40) per capsule, tan, yellowish brown, or brown, cochleate-reniform, papillose or tuberculate, arillate or not; endosperm scanty or none but a persistent perisperm sometimes present.
SELECTED REFERENCES Ernst, W. R. 1963b. The genera of Capparidaceae and Moringaceae in the southeastern United States. J. Arnold Arbor. 44: 81-95. Hall, J. C., H. H. Iltis, and K. J. Sytsma. 2004. Molecular phylogenetics of core Brassicales, placement of orphan genera Emblingia, Forchhammeria, Tirania, and character evolution. Syst. Bot. 29: 654-669. Hall, J. C., K. J. Sytsma, and H. H. Iltis. 2002. Phylogeny of Capparaceae and Brassicaceae based on chloroplast sequence data. Amer. J. Bot. 89: 1826-1842. Holmgren, P. K. and A. Cronquist. 2005. Cleomaceae. In: A. Cronquist et al. 1972+. Intermountain Flora. Vascular Plants of the Intermountain West, U.S.A. 6+ vols. in 7+. New York and London. Vol. 2, part B, pp. 160-174. Iltis, H. H. 1952. A Revision of the Genus Cleome in the New World. Ph.D. dissertation. Washington University. Iltis, H. H. 1957. Studies in the Capparidaceae. III. Evolution and phylogeny of the western North American Cleomoideae. Ann. Missouri Bot. Gard. 44: 77-119. Iltis, H. H. 1960. Studies in the Capparidaceae. VII. Old World cleomes adventive in the New World. Brittonia 12: 279-294. Kers, L. E. 2003. Capparaceae. In: K. Kubitzki et al., eds. 1990+. The Families and Genera of Vascular Plants. 9+ vols. Berlin etc. Vol. 5, pp. 36-56. Sánchez-Acebo, L. 2005. A phylogenetic study of the New World Cleome (Brassicaceae, Cleomoideae). Ann. Missouri Bot. Gard. 92: 179-201. Vanderpool, S. S., W. J. Elisens, and J. R. Estes. 1991. Pattern, tempo, and mode of evolutionary and biogeographic divergence in Oxystylis and Wislizenia (Capparaceae). Amer. J. Bot. 78: 925-937. Woodson, R. E. Jr. 1948. Gynandropsis, Cleome, and Podandrogyne. Ann. Missouri Bot. Gard. 35: 139-148.