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The families of flowering plants

L. Watson and M.J. Dallwitz

Meliaceae Juss.

Including Cedrelaceae R. Br.; excluding Aitoniaceae, Flindersiaceae.

Habit and leaf form. Trees, or shrubs (or suckering shrublets), or herbs (rarely, e.g. Naregamia); laticiferous (rarely, with milky juice exuding from the bark), or with coloured juice; bearing essential oils; resinous. Stem growth conspicuously sympodial (rarely), or not conspicuously sympodial. Often pachycaul. Mesophytic. Leaves alternate (nearly always), or opposite (rarely, decussate); nearly always spiral; petiolate; non-sheathing; commonly gland-dotted; without marked odour; compound (usually), or simple; pinnate (mostly), or unifoliolate (rarely), or ternate (rarely), or bifoliolate (very rarely), or bipinnate (very rarely); when pinnate, imparipinnate, or paripinnate. Lamina pinnately veined; cross-venulate. Leaves exstipulate. Lamina margins entire (usually), or crenate, or serrate, or dentate (or lobed). Vegetative buds scaly, or not scaly. Leaf development not ‘graminaceous’. Domatia occurring in the family (known from 6 genera); manifested as pits, or pockets, or hair tufts.

Leaf anatomy. The leaf lamina dorsiventral (often with secretory cells of various shapes and sizes containing resin, usually located between the palisade and the spongy mesophyll). Mucilaginous epidermis present, or absent. Stomata mainly confined to one surface (the lower); anomocytic. Hairs of numerous kinds present (in the family); eglandular and glandular; unicellular and multicellular. Unicellular hairs branched and simple. Multicellular hairs uniseriate and multiseriate; branched and simple. Complex hairs present, or absent; two-armed or stellate, or peltate. Adaxial hypodermis present (rarely), or absent. Lamina with secretory cavities (in a few genera, in addition to secretory cells), or without secretory cavities. Secretory cavities when present, containing resin. The mesophyll with sclerenchymatous idioblasts, or without sclerenchymatous idioblasts; containing crystals. The crystals druses and solitary-prismatic. Minor leaf veins without phloem transfer cells (Turraea).

Axial (stem, wood) anatomy. Pith homogeneous, or heterogeneous (often with resin cavities). Secretory cavities present (sometimes), or absent; when present, with resin. Cork cambium present; initially superficial. Nodes mostly penta-lacunar. Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring.

The wood diffuse porous (usually), or ring porous to semi-ring porous. The vessels from very small to medium, or large; radially paired to in radial multiples, or clustered, or in tangential arcs. The vessel end-walls simple. The vessels without vestured pits. The axial xylem with tracheids, or without tracheids (?); without vasicentric tracheids; with fibre tracheids, or without fibre tracheids; with libriform fibres, or without libriform fibres; including septate fibres, or without septate fibres. The fibres without spiral thickening. The parenchyma apotracheal, or paratracheal. The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones, or not stratified. ‘Included’ phloem absent. The wood storied to not storied. Tyloses absent (but deposits of gum common).

Reproductive type, pollination. Plants hermaphrodite (usually), or monoecious, or dioecious, or polygamomonoecious. Gynoecium of male flowers pistillodial, or vestigial (present as well developed rudiments, perhaps important in pollination). Pollination usually) entomophilous; via hymenoptera, or via lepidoptera; mechanism conspicuously specialized (passive pollen presenters, in at least three genera), or unspecialized.

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; when aggregated, in cymes, or in racemes, or in panicles, or in spikes. The ultimate inflorescence units cymose (usually, thyrsoid), or racemose. Inflorescences axillary (usually), or terminal, or leaf-opposed, or epiphyllous, or cauliflorous; usually paniculate with cymose branchlets (thyrsoid), less often racemose, fasciculate or spicate, or flowers paired or solitary. Flowers minute to large; calyptrate, or not calyptrate; regular; cyclic; tetracyclic to polycyclic. Floral receptacle with neither androphore nor gynophore. Free hypanthium absent. Hypogynous disk present, or absent; when present, intrastaminal; variable in form, stipitate, patelliform, cyathiform or tubular, free from or more or less fused with the bases of the staminal tube or ovary.

Perianth with distinct calyx and corolla; (5–)6–12(–21); 2 whorled, or 3 whorled (the corolla sometimes in two whorls); isomerous, or anisomerous. Calyx (2–)3–5(–7) (sometimes transitional to bracteoles); 1 whorled; gamosepalous (usually), or polysepalous; entire (occasionally, truncate or closed and circumcissile), or lobulate to blunt-lobed; regular; calyptrate (rarely), or not calyptrate; imbricate, or open in bud, or valvate (rarely, or almost closed when circumcissile). Corolla 3–7(–14); 1 whorled, or 2 whorled; polypetalous, or gamopetalous (rarely basally united, but often fused with the staminal tube); imbricate, or contorted, or valvate (less often).

Androecium (3–)5–10(–23), or 10–100 (to ‘many’, if appendages on the tube are treated as staminodial). Androecial members free of the perianth, or adnate (with the staminal tube adnate to the corolla); free of one another, or coherent (usually forming a staminal tube, which may be complete or incomplete, short or up to 14 cm long, globose, urceolate, campanulate, etc., or cylindrical and then sometimes curved or inflated distally, and which free or partially united appendages); when joined, 1 adelphous; 1–21 whorled (usually haplostemonous, sometimes with two stamen whorls, and up to many series of ‘appendages’). Androecium exclusively of fertile stamens, or including staminodes (the staminal tube being entire, crenate, lobed or bearing appendages). Staminodes when present, 5–100 (as many as the stamens, or twice the number, rarely up to ten times the number). Stamens (3–)5–10(–23); isomerous with the perianth, or diplostemonous; usually alternating with appendages, sometimes opposite them; filantherous, or petaloid, or petaloid and with sessile anthers (often with the anthers sessile on the corolla-like staminal tube). Anthers more or less dorsifixed; versatile; dehiscing via longitudinal slits; introrse; tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or decussate. Anther wall initially with more than one middle layer (2 or 3). Tapetum glandular. Pollen shed in aggregates (rarely), or shed as single grains; rarely in tetrads. Pollen grains aperturate; 2–5 aperturate; colporate (sometimes slightly ruporate); 2-celled (in 4 genera), or 3-celled (in Azadirachta only).

Gynoecium (1–)2–6(–20) carpelled. Carpels reduced in number relative to the perianth to increased in number relative to the perianth. The pistil (1–)2–6(–20) celled. Gynoecium syncarpous; synstylovarious, or eu-syncarpous; superior. Ovary (1–)2–6(–20) locular (reflecting the carpel number). Gynoecium non-stylate to stylate. Styles when demarcated, 1; when perceptible, attenuate from the ovary, or from a depression at the top of the ovary; apical. Stigmas 1; variously clavate, or capitate, or subpeltate to peltate (commonly forming a conspicuous receptaculum pollinis); wet type; papillate; Group III type. Placentation when unilocular (i.e. occasionally), parietal; usually axile. Ovules in the single cavity when unilocular 1, or 2, or 3–100 (i.e. one to ‘many’); 1–2 per locule (Melioideae), or 3–50 per locule (i.e. one to ‘many’, in Swietenioideae); usually pendulous; epitropous (micropyle superior); with ventral raphe; collateral, or superposed, or biseriate; arillate (Melioideae), or non-arillate (Swietenioideae); orthotropous, or anatropous, or campylotropous; bitegmic; crassinucellate. Outer integument contributing to the micropyle, or not contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids hooked (sometimes with filiform apparatus). Endosperm formation nuclear. Embryogeny onagrad.

Fruit fleshy, or non-fleshy; dehiscent, or indehiscent; a capsule, or a berry, or a drupe, or a nut (rarely). Capsules septicidal, or loculicidal. Seeds endospermic (rarely), or non-endospermic; winged (Swietenioideae), or wingless. Embryo well differentiated. Cotyledons 2. Embryo chlorophyllous (5/6), or achlorophyllous (3/4); straight, or curved.

Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, phytochemistry. Sugars transported as sucrose (e.g. in Cedrela), or as oligosaccharides + sucrose (in four other genera). Cyanogenic (?), or not cyanogenic. Alkaloids present (commonly), or absent. Iridoids detected (doubtfully, in Xylocarpus), or not detected (see Jensen 1991). Saponins/sapogenins present (rarely), or absent. Proanthocyanidins present, or absent; cyanidin. Flavonols present; quercetin, or kaempferol and quercetin. Ellagic acid absent (4 species, 3 genera). Aluminium accumulation not found.

Geography, cytology. Tropical (mostly), sub-tropical (few). Pantropical to subtropical and warm. X = 10–14(+).

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rutiflorae; Rutales. Cronquist’s Subclass Rosidae; Sapindales. APG III core angiosperms; core eudicot; Superorder Rosanae; malvid. APG IV Order Sapindales.

Species 575. Genera about 50; Aglaia, Amoora, Anthocarapa, Aphanamixis, Astrotrichilia, Azadirachta, Cabralea, Calodecarya, Capuronianthus, Carapa, Cedrela, Chisocheton, Chukrasia, Cipadessa, Dysoxylum, Ekebergia, Entandrophragma, Guarea, Heckeldora, Humbertioturraea, Khaya, Lansium, Lepidotrichilia, Lovoa, Malleastrum, Melia, Munronia, Naregamia, Neobeguea, Owenia, Pseudobersama, Pseudocarapa, Pseudocedrela, Pterorhachis, Reinwardtiodendron, Ruagea, Sandoricum, Schmardaea, Soymida, Sphaerosacme, Swietenia, Synoum, Toona, Trichilia, Turraea, Turraeanthus, Vavaea, Walsura, Xylocarpus.

General remarks. See Pennington and Styles 1975.

Economic uses, etc. Edible fruit from Lansium domesticum (langsat, ayer-ayer); and this family is perhaps of greater importance than any other as a source of hardwood timbers (Swietenia (Mahogany), Kaha (African mahogany), Cedrela and Toona (‘Cedars’), Lovoa (African walnut), etc.

Illustrations. • Le Maout and Decaisne: Melia, Swietenia. • Swietenia mahagoni: Lindley. • Trichilia retusa: Thonner. • Ekebergia senegalensis: Lindley. • Aglaia puberulanthera, as A. rubra: Hook. Ic. Pl. 31 (1916). • Dysoxylum spectabile, as Hartighsea: Hook. Ic. Pl. 7–8 (1844). • Dysoxylum pachyphyllum: Hook. Ic. Pl. 29 (1907). • Entandrophragma caudatum: Hook. Ic. Pl. 31 (1915). • Munronia pinnata (as Turraea(?) pinnata): Bot. Reg. 413, 1831. • Munronia unifoliolata: Hook. Ic. Pl. 18 (1887). • Turraea wakefieldii: Hook Ic. Pl. 15 (1885). • Turraea heterophylla: as T. lobata, Bot. Reg. 1844, 4.

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: 15th April 2018.’.