The genera of Leguminosae-Caesalpinioideae & Swartzieae
Type species: U. listeriana T.R. Sim.
Habit and leaf form. Small-leaved, evergreen trees; armed (with branches and twigs often transformed into spines).
The leaves compound; pinnate; paripinnate. The leaflets many per leaf; sessile, shining, sessile to sub-sessile; markedly asymmetrical (obliquely oblong); pinnately veined, with a predominant midrib (with the lateral veins ascending and much branched). Stipules absent or early caducous or very inconspicuous in mature leaves (absent). Stipels absent.
Inflorescence and floral morphology. The inflorescences on lateral branches; branched; panicles. The flowers not distichous. Bracteoles absent at anthesis.
The flowers small; hermaphrodite; actinomorphic; pentamerous. Hypanthium present. The perianth comprising distinct calyx and corolla. Calyx 5 (the segments short); not covering the rest of the flower in bud; campanulate, gamosepalous; more or less regular. Corolla present (perigynous); regular; 5; without greatly reduced members; polypetalous. Petals slightly imbricate; imbricate-ascending. The androecium comprising 10 members (perigynous); members all free of one another; members all more or less equal in length (spreading or slightly declinate); comprising only fertile stamens. Fertile stamens 10. Anthers attached well above the base of the connective (versatile, reniform); dehiscing longitudinally. Ovary sessile or subsessile. Stigma dilated (capitate, exserted). Ovules few (two).
Fruit, seed and seedling. Fruit a two-valved pod (this 1-seeded); thin, compressed, firmly membranous, not becoming woody.
Pollen ultrastructure. Tectum punctate; rugulose punctate. Length of colpi greater than one half pole to pole distance.
Species number and distribution. 1 species (U. listeriana). Southern Africa.
Tribe. Caesalpinieae (descriptive data inadequate, but cf. Gymnocladus and Gleditsia).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classification. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1993 onwards. The genera of Leguminosae-Caesalpinioideae and Swartzieae: descriptions, illustrations, identification, and information retrieval. In English and French. Version: 22nd March 2017. delta-intkey.com/caes’.