DELTA home

The families of flowering plants

L. Watson and M.J. Dallwitz

Stemonuraceae Karehed

Habit and leaf form. Trees and shrubs (buttressed in Cantleya, the lower branches self-pruning and leaving conspicuous scars in some genera); laticiferous, or non-laticiferous (?); leptocaul, or pachycaul. Helophytic, or mesophytic. Leaves persistent; alternate; spiral to distichous; leathery; petiolate; non-sheathing; not gland-dotted; simple. Lamina entire; pinnately veined (usually), or palmately veined (rarely); cross-venulate. Leaves exstipulate. Lamina margins entire to dentate. Vegetative buds distinctively cigar-shaped. Leaf development not ‘graminaceous’.

Leaf anatomy. Hydathodes present (occasionally?), or absent. Mucilaginous epidermis present, or absent (?). Stomata anomocytic, or anisocytic. Hairs of assorted unicellular and multicellular forms, present (?). Lamina with secretory cavities, or without secretory cavities (?). Secretory cavities if present, containing latex. The mesophyll with sclerenchymatous idioblasts, or without sclerenchymatous idioblasts.

Axial (stem, wood) anatomy. The cortex containing cristarque cells, or without cristarque cells (?). Secretory cavities present, or absent; when present, with latex. Cork cambium present; initially superficial. Nodes variously unilacunar, or tri-lacunar (?). Primary vascular tissues in a cylinder, without separate bundles, or comprising a ring of bundles, or comprising two or more rings of bundles, or consisting of scattered bundles (?); collateral, or bicollateral (?). Internal phloem present, or absent. Medullary bundles present, or absent. Secondary thickening developing from a conventional cambial ring (?).

The wood diffuse porous. The vessels very small to medium; solitary, or radially paired, or in radial multiples, or clustered, or in tangential arcs (in various combinations?). The vessel end-walls at least sometimes scalariform. The vessels without vestured pits; with spiral thickening, or without spiral thickening. The axial xylem with tracheids, or without tracheids; without vasicentric tracheids; commonly with fibre tracheids (in forms with scalariform perforation plates); with libriform fibres, or without libriform fibres; without septate fibres. The fibres without spiral thickening. ‘Included’ phloem absent. The wood not storied.

Reproductive type, pollination. Plants hermaphrodite, or monoecious, or andromonoecious, or gynomonoecious, or dioecious, or androdioecious, or gynodioecious, or polygamomonoecious, or polygamodioecious. Female flowers with staminodes, or without staminodes. Gynoecium of male flowers pistillodial.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’ (the pedicels articulated); in cymes, or in racemes (or leaf-apposed). The ultimate inflorescence units cymose. Inflorescences axillary, or leaf-opposed, or cauliflorous; usually axillary oe cauliflorous compound cymes. Flowers minute to small (mostly minute, but up to 1.5 cm in Whitmorea); odourless; regular; (4–)5(–7) merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk absent (usually), or present (?); when present, extrastaminal, or intrastaminal (?).

Perianth with distinct calyx and corolla; 8–12; 2 whorled; isomerous. Calyx 4–5(–7); 1 whorled; gamosepalous (generally cupular); blunt-lobed; cupuliform; regular; persistent; non-accrescent; imbricate (?). Corolla (4–)5(–7); 1 whorled; polypetalous, or gamopetalous. Corolla lobes markedly longer than the tube (sometimes dorsally keeled and inflexed). Corolla valvate; regular.

Androecium (4–)5(–6). Androecial members free of the perianth; all equal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 4–5(–7); isomerous with the perianth; oppositisepalous; alternating with the corolla members; filantherous (the filaments stout, with clavate hairs). Anthers basifixed; dehiscing via longitudinal slits; extrorse, or introrse; bisporangiate. Endothecium developing fibrous thickenings. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral. Anther wall initially with one middle layer to initially with more than one middle layer (these ephemeral). Tapetum glandular. Pollen grains aperturate; 3(–7) aperturate; colpate, or porate, or colporate, or foraminate (?).

Gynoecium 2 carpelled. Carpels reduced in number relative to the perianth. The pistil 1 celled. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary unilocular; 1 locular (by abortion). Gynoecium shortly non-stylate to stylate. Styles 1; attenuate from the ovary; apical; shorter than the ovary. Stigmas entire or lobed; peltate, subcapitate or punctiform. Ovules in the single cavity usually 2 (back to back — rarely only one); pendulous; arillate (with a funicular thickening near the micropyle), or non-arillate (?); anatropous; unitegmic; crassinucellate (at least in Stemonurus).

Fruit fleshy to non-fleshy; indehiscent; a drupe (often with a fleshy lateral appendage); 1 seeded. Seeds minute to small.

Geography, cytology. Paleotropical, Neotropical, and Australian. Sub-tropical and tropical. More or less pan-tropical: northern S. America, tropical W. Africa, Madagascar, Comores, Seychelles, S. India, Sri Lanka, trop. S.E. Esia, Malesia, N. Australia.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli (?). Dahlgren’s Superorder Corniflorae; Cornales. Cronquist’s Subclass Rosidae; Celastrales. APG III core angiosperms; core eudicot; Superorder Asteranae; campanulid. APG IV Order Aquifoliales.

Species about 70. Genera 12; Cantleya, Codiocarpus, Discophora, Gastrolepis, Gomphandra, Grisollea, Hartleya, Irvingbaileya, Lasianthera, Medusanthera, Stemonurus, Whitmorea.

General remarks. See (e.g.) Potgieter M.J., Schori M., Utteridge T.M.A. (2016): Stemonuraceae, in Kadereit J., Bittrich V. (eds) Flowering Plants. Eudicots. The Families and Genera of Vascular Plants, vol 14. Springer, Cham. This unsatisfactory draft description, consequent on segregation of these genera from Icacinaceae (q.v.), needs critical attention - especially re anatomy, embryology and phytochemistry.

Illustrations. • Grisollea thomassetii: Hook. Ic. Pl. 28 (1905). • Codiocarpus merrittii: Sleumer, Fl. Malesiana 7 (1971). • Hartleya inopinata: Sleumer, Fl. Malesiana 7 (1971). • Medusanthera laxiflora: Sleumer, Fl. Malesiana 7 (1971). • Stemonurus malaccensis: Sleumer, Fl. Malesiana 7 (1971). • Whitmorea grandiflora: Sleumer, Fl. Malesiana 7 (1971).

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: 5th March 2018.’.