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The genera of Leguminosae-Caesalpinioideae & Swartzieae

L. Watson and M.J. Dallwitz

Swartzia Schreber

Including Bobgunnia Kirkbride & Wiersema (S. fistuloides, S. madagascariensis), Cyathostegia Schery (S. matthewsii, S. weberbaueri), Fairchildia Britton & Rose (S. panamensis). Cf. also Ateleia p.p. (e.g., S. gummifera)

Type species: S. guianensis (Aubl.) Urb. (S. alata Willd.).

Habit and leaf form. Trees, or shrubs, or climbers or scramblers (rarely); without tendrils (the foliage not foetid); unarmed.

Phyllotaxy spiral. The leaves compound, or ostensibly simple (rarely); when ostensibly simple, pinnately veined with a predominant midrib; when compound, i.e. usually, pinnate; usually imparipinnate. The leaflets opposite or sub-opposite (usually); petiolulate; without noticeably twisted petiolules; symmetrical or nearly so; with a predominant ‘midrib’. Stipules absent or early caducous or very inconspicuous in mature leaves, or present, persistent and conspicuous in mature leaves (rarely); membranous. Stipels present, or absent.

Inflorescence and floral morphology. The flowers aggregated into inflorescences (usually), or solitary. The inflorescences often at older nodes or flowering on leafless branchlets; unbranched, or branched; of racemose units; simple racemes, or fascicles, or panicles. The flowers not distichous. Bracts absent at anthesis. Bracteoles present; small, not enclosing the flower buds; absent at anthesis, or persistent beyond anthesis.

The flowers hermaphrodite; not pentamerous throughout; departing from pentamery in the calyx, in the corolla, and in the androecium. Floral tube length relative to total hypanthium + calyx length about 0.75–1. Hypanthium absent, the androecium hypogynous. The perianth comprising distinct calyx and corolla, or exclusively sepaline. Calyx irregularly 2–5; covering the rest of the flower in bud; Swartzieae type (closed before flowering, splitting more or less irregularly into valvate lobes or teeth); gamosepalous; members not imbricate. Corolla present, or absent; when present, very irregular; 0, or 1; without greatly reduced members; when present, monopetalous. Disk absent. The androecium comprising 30–50 members; declinate; with united members (rarely), or members all free of one another; members all more or less equal in length, or markedly unequal (often exhibiting two or three stamens with filaments much longer than the majority); comprising only fertile stamens. Fertile stamens 30 (or more). Anthers attached well above the base of the connective (dorsifixed, ovoid or oblate to oblong, much shorter than the filaments); dehiscing longitudinally. Ovary stipitate; free. Stigma small but dilated, or not dilated. Ovules numerous.

Fruit, seed and seedling. Fruit a two-valved pod, or indehiscent; straight; becoming woody, or not becoming woody. Seeds endospermic, or non-endospermic; arillate; with an inflexed radicle; amyloid-negative; with starch. Cotyledons not flat.

Transverse section of lamina. Leaves without conspicuous phloem transfer cells in the minor veins. Druses absent from the mesophyll. Mesophyll secretory cavities absent. Adaxial hypodermis absent. Leaf girders common (the veins transcurrent). Laminae isobilateral, with adaxial and abaxial palisades, or 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; scabrid, or smooth. 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 absent. Adaxial: Adaxial interveinal epidermal cell walls straight in optical section; conspicuously pitted, or not conspicuously pitted; 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.

Wood anatomy. Wood without septate fibres; storied; without normal intercellular canals; without traumatic canals. Intervascular pits medium to large.

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

Cytology. Basic chromosome number, x = 8 (Africa), or 14.

Species number and distribution. About 135 species. Tropical America, Africa.

Tribe. Papilionoideae-Swartzieae.

Miscellaneous. Illustrations: • S. conferta and S. racemosa: Fl. Brasiliensis 15 (1870). • S. langsdorfii: Fl. Brasiliensis 15 (1870). • S. flemmingii: Fl. Brasiliensis 15 (1870). • S. sericea: Fl. Brasiliensis 15 (1870). • S. dicarpa (= S. dipetala?) and S. microcarpa: Fl. Brasiliensis 15 (1870). • S. matthewsii (= Cyathostegia): Hook. Ic. Pl. 11 (1867). • Swartzia sp. (as Tounatea pulchra): Nat. Pflanzenfam. III (1894). • S. grazielana leaflet: adaxial epidermis. • S. panamensis: Schery, Ann. Miss. Bot. Gard. 38 (1951). • S. nuda: Schery, Ann. Miss. Bot. Gard. 38 (1951). • S. simplex: Schery, Ann. Miss. Bot. Gard. 38 (1951).

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.’.