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The genera of Leguminosae-Caesalpinioideae & Swartzieae

L. Watson and M.J. Dallwitz

Aprevalia Baill.

~ Delonix.

Type species: A. floribunda Baill.

Habit and leaf form. Deciduous, umbrella-shaped trees (with twisted branches); unarmed.

Phyllotaxy spiral. The leaves compound; bipinnate (with 1–3(-6) pairs of pinnae); with opposite or sub-opposite pinnae; with opposite or sub-opposite leaflets; with adaxially grooved rachides. The leaflets many per leaf ((8-)12–20 of them per pinna); very shortly petiolulate, or sessile to sub-sessile; without noticeably twisted petiolules; symmetrical or nearly so; with a predominant ‘midrib’; without a continuous marginal nerve. Stipels absent.

Inflorescence and floral morphology. The inflorescences sometimes subtended by developing leaves, usually on leafless shoots or below young leaves; branched (shortly racemose-paniculate, precocious, the racemes combining into dense, flat-topped, leafless corymbs). The flowers not distichous. Bracts absent at anthesis. Bracteoles absent at anthesis.

The flowers hermaphrodite; very irregular (at least with reference to the reduced corolla, this being the principal or only conspicuous difference from Delonix sensu stricto); not pentamerous throughout; departing from pentamery in the corolla and in the androecium; coloured. Hypanthium present; short. The perianth comprising distinct calyx and corolla (but the corolla reduced). Calyx present; 5; covering the rest of the flower in bud; polysepalous; more or less regular; members not imbricate (valvate). Corolla present; very irregular; 1–5 (only the adaxial being one well developed, and this small); usually including greatly reduced members. Well developed petals 1 (this small and narrow). Vestigial petals when present, 1–4 (lateral and abaxial). Corolla polypetalous, or monopetalous. Petals clawed (i.e., the well developed member); yellow. Disk absent. The androecium comprising 10 members; not declinate; members all free of one another; members biseriate, but all more or less equal in length; comprising only fertile stamens. Fertile stamens 10. Anthers attached well above the base of the connective; dehiscing introrsely; dehiscing longitudinally. Ovary tomentose, sessile or subsessile; free. Stigma not dilated. Ovules numerous.

Fruit, seed and seedling. Fruit a two-valved pod; straight (linear-oblong); internally septate (?); without markedly twisting or enrolling valves; becoming woody. The mature valves without prominent venation.

Species number and distribution. 1–2 species (A. floribunda and A. perrieri). Madagascar.

Tribe. Caesalpinieae.

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.’.