The Genera of Leguminosae-Caesalpinioideae and Swartzieae

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L. Watson and M. J. Dallwitz

Arapatiella Rizzini & Mattos

Habit and leaf form. Trees; without tendrils; unarmed. Phyllotaxy spiral. Leaves compound; pinnate; imparipinnate, or paripinnate; with adaxially grooved rachides. Leaflets few per leaf (2–3 jugate); opposite or sub-opposite; petiolulate. Stipules present, persistent and conspicuous; leafy; not connate. Stipels absent.

Inflorescence and floral morphology. Flowers hermaphrodite; pentamerous; in simple racemes, or in panicles; distichous. Inflorescences axillary and terminal; of racemose units. Bracteoles present; small, not enclosing the flower buds; absent at anthesis; not valvate. Hypanthium present. Calyx polysepalous; covering the rest of the flower in bud; 5 partite; imbricate. Corolla present; polypetalous; without any greatly reduced petals. Petals white; 5; imbricate. Clawed petals present. Androecium of ten parts; without staminodia. Fertile stamens 10. Anthers attached well above base of connective (versatile). Dehiscence introrse; longitudinal. Ovary stipitate; free. Stigma peltate. Ovules numerous (6–8).

Fruit, seed and seedling. Fruit a two-valved pod; not becoming woody; not winged; valves twisting and enrolling during dehiscence (revolute).

Transverse section of lamina. Druses 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 not seen. Expanded and embedded hair-feet absent. Basally bent hairs present. Adaxial interveinal epidermal cell walls straight in optical section; conspicuously pitted; of medium thickness. Stomata adaxially very rare. Abaxial stomata predominantly paracytic. Abaxial epidermis not papillate. Abaxial interveinal epidermal cell walls straight, or gently undulating and markedly sinuous in high-focus optical section; conspicuously pitted in optical section; staining normally with safranin; of medium thickness.

Pollen ultrastructure. Tectum reticulate; strongly irregularly coarse-reticulate (without a margocolpus).

Cytology, geography, etc. 2 species. Brazil. Not widely cultivated.

Tribe. Caesalpinieae.


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Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1993 onwards. The genera of Leguminosae-Caesalpinioideae and Swartzieae: descriptions, identification, and information retrieval. In English and French; French translation by E. Chenin. Version: 19th October 2005. http://delta-intkey.com’.

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