The genera of Leguminosae-Caesalpinioideae & Swartzieae
Type species: P. discolor Vogel.
Habit and leaf form. Trees; unarmed.
Phyllotaxy spiral. The leaves compound; bifoliolate; paripinnate. The leaflets glandular-punctate, few per leaf (two only, these somewhat inequilateral and pinnately veined); petiolulate to sessile to sub-sessile; without noticeably twisted petiolules; without a continuous marginal nerve. Stipules absent or early caducous or very inconspicuous in mature leaves. Stipels absent.
Inflorescence and floral morphology. The inflorescences terminal; branched; of racemose units; panicles (of short racemes). The flowers not distichous. Bracts small, caducous, absent at anthesis. Bracteoles present; small, not enclosing the flower buds; persistent beyond anthesis, or absent at anthesis; not valvate; shortly connate, or free.
The flowers hermaphrodite; not pentamerous throughout; departing from pentamery in the calyx; white or green, or coloured. Floral tube length relative to total hypanthium + calyx length about 0.25. Hypanthium present; thick, shortly cupular, or tubular, or campanulate. The perianth comprising distinct calyx and corolla. Calyx 4; covering the rest of the flower in bud; not Swartzieae type; polysepalous; members very imbricate. Corolla present; regular to slightly irregular; 5; without greatly reduced members; polypetalous. Petals sessile, or clawed to sessile; oblong to obovate, only slightly unequal but the adaxial, innermost one often narrower; imbricate-ascending; white, or yellow. Disk present and conspicuous (comprising nectarial tissue almost filling the hypanthium). The androecium comprising 10 members; not declinate; members all free of one another; members all more or less equal in length (glabrous); comprising only fertile stamens. Fertile stamens 10. Anthers attached well above the base of the connective. Ovary shortly stipitate; eccentric, with the stipe adnate. Stigma at least sometimes, dilated (then capitate, on the barely exserted style). Ovules few.
Fruit, seed and seedling. Fruit a two-valved pod (usually), or indehiscent (resin-dotted); narrowly winged longitudinally (along the upper suture), or not noticeably winged; compressed, obliquely orbicular to subtriangular, usually 1(-2)seeded, becoming woody, or not becoming woody. The mature valves reticulately veined. Seeds non-endospermic; arillate, or not arillate; with a straight or slightly oblique radicle; amyloid-positive. Cotyledons of Type 4; with a vascular system in one plane.
Transverse section of lamina. Leaves with conspicuous phloem transfer cells in the minor veins. Druses absent from the mesophyll. Mesophyll secretory cavities (gland-dots) common; epithelium-lined. Adaxial hypodermis absent. Leaf girders absent. Laminae dorsiventral. Mesophyll without unaligned fibres or sclereids. Minor veins mainly with abundant accompanying fibres.
Leaf lamina epidermes. Epidermal crystals present, or not seen either adaxially or abaxially; druses. Simple unbranched hairs common, or not seen; 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 present; all medium to thick-walled; hair feet all simple, without vertical walls. Basally bent hairs present. Adaxial: Adaxial interveinal epidermal cell walls straight in optical section; not conspicuously pitted. Stomata adaxially very rare. Abaxial: Abaxial stomata predominantly paracytic. Abaxial epidermis not papillate. Abaxial interveinal epidermal cell walls straight, or gently undulating, or markedly sinuous in high-focus optical section; not conspicuously pitted in optical section; staining normally with safranin.
Wood anatomy. Wood without septate fibres; storied, or not storied; without normal intercellular canals; with traumatic canals. Intervascular pits very small, or medium to large.
Pollen ultrastructure. Tectum reticulate; rugulose reticulate.
Species number and distribution. About 25 species. Tropical South America, Mexico, West Indies.
Tribe. Detarieae; Detarieae sensu stricto clade of Bruneau et al. (2008).
Miscellaneous. Illustrations: • P. venosa subsp. densiflora and P. paniculata: Fl. Brasiliensis 15 (1870). • P. parvifolia and P. discolor, 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. delta-intkey.com/caes’.