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The families of flowering plants

L. Watson and M. J. Dallwitz

Scytopetalaceae Engl.

~ Lecythidaceae.

Including Rhaptopetalaceae Pierre ex Van Tiegh.

Habit and leaf form. Trees, shrubs, and herbs. Leaves alternate; spiral, or distichous (usually, at least on the side shoots); leathery; shortly petiolate to sessile; simple. Lamina entire; pinnately veined; often asymmetric at the base. Leaves exstipulate. Lamina margins entire, or dentate.

General anatomy. Plants with silica bodies (?).

Leaf anatomy. The leaf lamina dorsiventral (usually), or dorsiventral to bifacial (the palisade being sometimes indistinct). Stomata present; mainly confined to one surface, or on both surfaces; anisocytic. Hairs present, or absent; when present, eglandular; unicellular. Unicellular hairs simple. Lamina without secretory cavities. The mesophyll without etherial oil cells; not containing mucilage cells; with sclerenchymatous idioblasts (at least usually?).

Axial (stem, wood) anatomy. The cortex containing cristarque cells (Scytopetalum, Oubanguia), or without cristarque cells (Rhaptopetalum). Cork cambium present; initially superficial. Primary vascular tissues in a cylinder, without separate bundles (traversed by rays 1–3 cells wide); collateral. Internal phloem absent. Cortical bundles present (two to several, with normal orientation), or absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays narrow.

The vessel end-walls simple, or scalariform and simple. The vessels without vestured pits. The axial xylem with fibre tracheids, or without fibre tracheids; with libriform fibres, or without libriform fibres. The parenchyma apotracheal. The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones.

Reproductive type, pollination. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes, or in panicles. Inflorescences terminal (panicles), or axillary (racemes), or cauliflorous; terminal panicles or axillary racemes, or in clusters on the old wood. Flowers calyptrate, or not calyptrate; regular. Free hypanthium absent. Hypogynous disk present, or absent; extrastaminal, or intrastaminal (‘intrastaminal disk mostly absent’).

Perianth sepaline (but with a staminodial pseudo-corolla); 1 whorled. Calyx completely fused, the number of components probably not indicated by the splitting; 1 whorled; gamosepalous; entire, or toothed (by tearing during anthesis); shortly cupuliform; regular; leathery, persistent; non-accrescent; valvate (when toothed,), or open in bud (?).

Androecium (10–)20–100 (to ‘many’). Androecial members branched (? — tending to be clustered), or unbranched; maturing centrifugally; free of the perianth; coherent (the staminodes connate to form the pseudocorolla, the stamens usually adnate to it and to one another); 2 whorled (with an outer staminodal whorl, and the stamens in a single, dense ring, not resolvable into series). Androecium including staminodes. Staminodes 6–16 (but not always individually resolvable); external to the fertile stamens; petaloid (thick and leathery, rupturing at anthesis). Stamens (10–)20–240 (to ‘many’); isomerous with the perianth to polystemonous; filantherous (the anthers relatively long (e.g. Rhaptopetalum) or short, e.g. Scytopetalum). Anthers basifixed; non-versatile; dehiscing via pores to dehiscing via short slits (these obliquely terminal, Brazzeia, Rhaptopetalum, Perrierina), or dehiscing via longitudinal slits; bilocular; tetrasporangiate. Tapetum glandular. Pollen shed as single grains. Pollen grains aperturate; 3 aperturate; colpate, or colporate (then colporoidate); 2-celled.

Gynoecium 3–8 carpelled. Carpels reduced in number relative to the perianth to increased in number relative to the perianth. The pistil 1 celled, or 3–8 celled. Gynoecium syncarpous; eu-syncarpous; superior (mostly), or superior to partly inferior (Rhaptopetalum). Ovary 3–8 locular (but the partitions sometimes apically incomplete); sessile. Gynoecium stylate. Styles 1; attenuate from the ovary; apical; about as long as the ovary to much longer than the ovary. Stigmas 1 (small); 1 lobed (Rhaptopetalum), or 3–8 lobed. Placentation axile to apical. Ovules 2–8 per locule; funicled; pendulous to horizontal; biseriate; anatropous; bitegmic; tenuinucellate (according to Cronquist).

Fruit somewhat fleshy (Scytopetalum), or non-fleshy (often woody); dehiscent (Oubanguia), or indehiscent; a capsule (Oubanguia), or capsular-indehiscent (mostly), or a drupe (Scytopetalum, with lignified mesocarp). Capsules of Oubanguia loculicidal. The drupes with separable pyrenes (unilocular). Fruit 1–8 seeded. Seeds copiously endospermic. Endosperm ruminate (mostly), or not ruminate (sometimes, in Oubanguia). Seeds conspicuously hairy (sometimes, with agglutinated mucilaginous hairs), or not conspicuously hairy. Seeds without starch. Seeds with amyloid. Embryo well differentiated. Cotyledons 2 (large, thin, leafy); flat. Embryo straight.

Physiology, phytochemistry. Aluminium accumulation demonstrated, or not found.

Geography, cytology. Tropical. West tropical Africa. X = 11, 18.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Theiflorae; Theales. Cronquist’s Subclass Dilleniidae; Theales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; Order Ericales (as a synonym of Lecythidaceae).

Species 20. Genera 5; Brazzeia, Oubanguia, Pierrina, Rhaptopetalum, Scytopetalum.

General remarks. See Appel 1986. Morton et al. (1998) treat these genera, plus Asteranthos (cf. Asteranthaceae), as subfamily Scytopetaloideae of their expanded Lecythidaceae.

Illustrations. • Scytopetalum klaineanum: Nat. Pflanzenfam. III (1897). • Technical details: Rhaptopetalum sessilifolium (Thonner). • Rhaptopetalum soyauxii: Hook. Ic. Pl. 15 (1883–85).

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, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 19th October 2016.’.