The genera of Leguminosae-Caesalpinioideae & Swartzieae
Isomacrolobium Aubrév. & Pellegr., Triplisomeris Aubrév. & Pellegr., Leonardendron Aubrév., and numerous species of Vouapa Aubl.
Type species: A. macrophylla P. Beauv.
Habit and leaf form. Trees; unarmed.
Phyllotaxy spiral. The leaves compound; pinnate; paripinnate. The leaflets many per leaf; opposite or sub-opposite; petiolulate; without noticeably twisted petiolules; symmetrical or nearly so; pinnately veined, with a predominant midrib; without a continuous marginal nerve. Stipules absent or early caducous or very inconspicuous in mature leaves; membranous; connate, or not connate. Stipels absent.
Inflorescence and floral morphology. The inflorescences mostly branched; of racemose units; panicles. The flowers not distichous. Bracts absent at anthesis. Bracteoles present; small, not enclosing the flower buds, or relatively large and enclosing the flower buds; persistent beyond anthesis; valvate.
The flowers hermaphrodite; pentamerous (A. gabunense), or not pentamerous throughout; departing from pentamery usually in the calyx, in the corolla, and in the androecium. Floral tube length relative to total hypanthium + calyx length about 0.25. Hypanthium present; shortly cupular, or tubular. The perianth comprising distinct calyx and corolla. Calyx 4–5; polysepalous; more or less regular, or markedly irregular. Corolla present; regular, or slightly irregular, or very irregular; 2–6; including greatly reduced members, or without greatly reduced members; polypetalous. The androecium comprising 4–9(–12) members; with united members, or members all free of one another; members markedly unequal; including staminodia, or comprising only fertile stamens (A. gabunense). The staminodia (1–)5–6(–7). Fertile stamens 3(–5). Anthers attached well above the base of the connective; dehiscing longitudinally. Ovary sessile or subsessile; eccentric, with the stipe adnate. Stigma not dilated. Ovules few, or numerous, or solitary.
Fruit, seed and seedling. Fruit a two-valved pod; valves twisting and enrolling during dehiscence, or without markedly twisting or enrolling valves; becoming woody. The mature valves with conspicuous, prominent, raised venation; conspicuous venation oblique, not predominantly longitudinal. Seeds not arillate; with a straight or slightly oblique radicle; amyloid-positive. Cotyledons not flat; hypogeal.
Transverse section of lamina. Druses common in the mesophyll, or absent from the mesophyll. Mesophyll secretory cavities absent. Adaxial hypodermis absent. Leaf girders common (the veins transcurrent). Laminae dorsiventral. Mesophyll without unaligned fibres or sclereids. Minor veins mainly with abundant accompanying fibres.
Leaf lamina epidermes. Epidermal crystals not seen either adaxially or abaxially. Simple unbranched hairs common; smooth. No compound or branched eglandular hairs seen. Capitate glands not seen. Hooked hairs not seen. Cassieae-type leaf pseudo-glands present, or not seen. Expanded and embedded hair-feet present, or absent; (at least some of them) thin-walled; hair feet all simple, without vertical walls. Basally bent hairs absent. Adaxial: Adaxial interveinal epidermal cell walls straight in optical section; not conspicuously pitted; thick to medium-thick. Stomata adaxially very rare. Abaxial: Abaxial stomata predominantly paracytic. Abaxial epidermis not papillate. Abaxial interveinal epidermal cell walls straight, or gently undulating; conspicuously pitted in optical section, or not conspicuously pitted in optical section; staining normally with safranin.
Cytology. Basic chromosome number, x = 12. 2n = 24.
Species number and distribution. About 30 species. Tropical Africa.
Tribe. Detarieae (Amherstieae of Cowan and Polhill 1981); Amherstieae clade of Bruneau et al. (2008).
Miscellaneous. Illustrations: • A. noldeae: Brenan, Fl. Tropical East Africa (1967). • A. ferruginea (as Macrolobium): Engler & Drude, Pflanzenwelt Afrikas 9 (1915). • A. macrophylla (as Macrolobium): Leonard, Fl. du Congo Belge (1952). • A. macropylla (as Vouapa), with Gibertiodendron demonstrans (as Vouapa) and Berlinia spp.: Baillon, Adansonia VI (1865). • A. gabunense (as Leonardendron): Aubréville, Flore du Gabon (1968). • A. fragrans: Aubréville, Flore du Gabon (1968).
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’.