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The genera of Leguminosae-Caesalpinioideae & Swartzieae

L. Watson and M.J. Dallwitz

Macrolobium Schreb.

Outea Aubl., Vouapa Aubl. p.p., Utea (Aubl.) St. Hil., Vuapa (Aubl.) St. Hil., Pseudovouapa Britton & Killip

Type species: M. bifolium (Aubl.) Pers.

Habit and leaf form. Trees, or shrubs; unarmed.

Phyllotaxy distichous, or spiral. The leaves compound; pinnate, or bifoliolate (rarely); paripinnate. The leaflets many per leaf, or few per leaf; opposite or sub-opposite; petiolulate, or sessile to sub-sessile; with markedly twisted petiolules (rarely), or without noticeably twisted petiolules; markedly asymmetrical to 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, or present, persistent and conspicuous in mature leaves; leafy, or membranous. Stipels absent.

Inflorescence and floral morphology. The inflorescences unbranched and branched; of racemose units; simple racemes, or panicles (the racemes sometimes shortly branched). The flowers not distichous. Bracts absent at anthesis. Bracteoles present; relatively large and enclosing the flower buds; persistent beyond anthesis; valvate.

The flowers hermaphrodite; not pentamerous throughout; departing from pentamery in the corolla and in the androecium, or in the calyx, in the corolla, and in the androecium (rarely). Floral tube length relative to total hypanthium + calyx length about 0.5. Hypanthium present; asymmetrically cupular to tubular. The perianth comprising distinct calyx and corolla. Calyx 4–5; covering the rest of the flower in bud; polysepalous; more or less regular, or markedly irregular; members imbricate. Corolla present; very irregular; 1, or 2–5 (rarely, with vestiges); including greatly reduced members, or without greatly reduced members; polypetalous. Petals clawed, or sessile, or clawed and sessile. The androecium comprising 3 members (usually); tending to declinate; members all free of one another; members all more or less equal in length, or markedly unequal (rarely); including staminodia (rarely?), or comprising only fertile stamens. Fertile stamens with filiform filaments, 3. Anthers attached well above the base of the connective; dehiscing longitudinally. Ovary stipitate; eccentric, with the stipe adnate. Stigma small, but dilated, or not dilated. Ovules few, or numerous, or solitary.

Fruit, seed and seedling. Fruit a follicle, or a two-valved pod, or indehiscent; oval or orbicular to oblong. The mature valves without prominent venation. Seeds non-endospermic; with a straight or slightly oblique radicle; amyloid-positive. Cotyledons of Type 4; with a vascular system in one plane; epigeal.

Transverse section of lamina. Leaves with conspicuous phloem transfer cells in the minor veins. Druses common in the mesophyll, or absent from the mesophyll. Mesophyll secretory cavities absent. Adaxial hypodermis absent. Leaf girders absent. Laminae dorsiventral. Mesophyll exhibiting fibres or sclereids which are unaligned with the vascular bundles, or 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, or not seen; scabrid. No compound or branched eglandular hairs seen. Capitate glands not seen. Hooked hairs not seen. Cassieae-type leaf pseudo-glands not seen. Expanded and embedded hair-feet present; (at least some of them) thin-walled; hair feet all simple, without vertical walls. Adaxial: Adaxial interveinal epidermal cell walls straight in optical section, or markedly sinuous in high-focus optical section; not conspicuously pitted. Stomata adaxially very rare. Abaxial: Abaxial stomata predominantly paracytic. Abaxial epidermis papillate interveinally, or not papillate; with papillae over-arching the stomata. 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; medium-thin.

Wood anatomy. Wood not storied; with traumatic canals. Intervascular pits very small.

Pollen ultrastructure. Tectum striate; pole to pole striate. Length of colpi greater than one half pole to pole distance.

Species number and distribution. About 50 species. Tropical America.

Tribe. Detarieae (Amherstieae of Cowan and Polhill 1981); Amherstieae clade of Bruneau et al. (2008).

Comments. Widely cultivated.

Miscellaneous. Illustrations: • M. limbatum and M. punctatum: Fl. Brasiliensis 15 (1870). • M. multijugum and M. taxifolium: Fl. Brasiliensis 15 (1870). • M. modicopetalum: Schery, Ann. Miss. Bot. Gard. 38 (1951). • M. macrophyllum, e.m. scanned pollen (Graham & Barker, 1981).

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.’.