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The families of flowering plants

L. Watson and M. J. Dallwitz

Polygalaceae Juss.

Including Diclidantheraceae J.G. Agardh, Disantheraceae Dulac, Moutabeae (Moutabeaceae) Endl.; excluding Emblingiaceae, Xanthophyllaceae.

Habit and leaf form. Trees, shrubs, and herbs, or lianas (rarely, small); bearing essential oils, or without essential oils. Switch-plants (sometimes), or ‘normal’ plants; sometimes with the principal photosynthesizing function transferred to stems. Plants autotrophic (mostly), or partially parasitic (Salomonia). Parasitic on roots of the host (i.e., Salomonia). Without conspicuous aggregations of leaves. Self supporting, or climbing (a few). Mesophytic, or xerophytic. Leaves alternate, or opposite, or whorled; usually spiral; ‘herbaceous’, or leathery, or membranous; petiolate to subsessile; non-sheathing; gland-dotted, or not gland-dotted; simple. Lamina entire; pinnately veined; cross-venulate. Leaves stipulate, or exstipulate. Stipules when present, intrapetiolar; free of one another; often scaly, or spiny, or represented by glands. Lamina margins entire. Leaf development not ‘graminaceous’.

Leaf anatomy. The leaf lamina varied in anatomical layout, dorsiventral, or bifacial, or centric. Stomata anomocytic (usually), or paracytic. Hairs present; exclusively eglandular; almost exclusively unicellular, or multicellular (rarely becoming uniseriate). Complex hairs absent. Adaxial hypodermis absent (nearly always), or present (in Moutabea). Lamina with secretory cavities (Polygala erioptera), or without secretory cavities. Secretory cavities when present, containing oil; lysigenous. The mesophyll usually containing crystals, or without crystals (e.g., none recorded in Bredemeyera). The crystals solitary-prismatic, or druses and solitary-prismatic. Minor leaf veins without phloem transfer cells (Polygala).

Axial (stem, wood) anatomy. Cork cambium present; initially superficial. Nodes unilacunar. Primary vascular tissues in a cylinder, without separate bundles (mostly), or comprising a ring of bundles (in a few Polygala species); collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring (often, but the interfascicular cambium sometimes not generating vessels), or anomalous (commonly: see illustration). The anomalous secondary thickening commonly via concentric cambia. The axial xylem with vessels.

The wood diffuse porous. The vessels small to medium (in most genera), or large (e.g., in Securidaca); solitary (typically almost exclusively so), or radially paired, or in radial multiples, or clustered, or in tangential arcs. The vessel end-walls slightly oblique, or horizontal; simple. The vessels without vestured pits; commonly with spiral thickening. The axial xylem with tracheids (e.g.Diclidantheraceae), or without tracheids; often with vasicentric tracheids; with fibre tracheids (Securidaca), or without fibre tracheids; at least sometimes including septate fibres, or without septate fibres (?). The fibres at least sometimes with spiral thickening. The parenchyma paratracheal (predominantly, in Polygaleae), or apotracheal (in Moutabeae). ‘Included’ phloem present (commonly), or absent. The wood not storied. Tyloses absent (usually), or present (e.g., in Moutabea).

Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite. Pollination entomophilous; mechanism conspicuously specialized (via passive presenters), or unspecialized.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in panicles, in racemes, and in spikes. The ultimate inflorescence units cymose. Inflorescences spikes, racemes or panicles, the pedicels often articulated; pseudanthial (e.g., Polygala sanguinea), or not pseudanthial (mostly). Flowers bracteate; bracteolate; small, or medium-sized; very irregular; medianly zygomorphic. The floral irregularity involving the perianth and involving the androecium. Flowers ‘pseudo-papilionaceous’; cyclic; pentacyclic. Free hypanthium absent. Hypogynous disk present, or absent; annular (around G).

Perianth with distinct calyx and corolla; 8, or 10; 2 whorled; usually anisomerous. Calyx 5 (the two inner, posterior-lateral members often large and petaloid); 1 whorled; polysepalous (usually), or partially gamosepalous (then the two lower members joined basally), or gamosepalous (with a short tube); imbricate; with the median member posterior. Corolla 3(–5) (declinate, usually three only and consisting of the posterior pair and an often dorsally keeled and fringed anterior-median); 1 whorled; gamopetalous (at the base, and adnate to the staminal tube), or polypetalous. Corolla lobes markedly longer than the tube. Corolla unequal but not bilabiate (zygomorphic, the median anterior member keel-like, the upper two members free, minute or lacking). Petals fringed (the boat-shaped lower median often so), or entire.

Androecium 8 (usually, supposedly derived by suppression of the median member of each of the two whorls), or 10, or 3–7. Androecial members adnate (usually, to the corolla), or free of the perianth; coherent (usually), or free of one another (rarely); nearly always 1 adelphous (the filaments usually united below into a split tube, this often adnate to the corolla); 1 whorled, or 2 whorled. Androecium exclusively of fertile stamens. Stamens 3–10; reduced in number relative to the adjacent perianth, or isomerous with the perianth, or diplostemonous. Anthers basifixed; dehiscing via pores, or dehiscing via short slits, or dehiscing via longitudinal slits (rarely), or dehiscing by longitudinal valves; unilocular to bilocular; bisporangiate (by reduction), or tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral. Anther wall initially with one middle layer, or initially with more than one middle layer (1 or 2); of the ‘dicot’ type. Tapetum glandular. Pollen grains aperturate; 7–30 aperturate; colporate (polycolporate, often synorate); 2-celled (in Salomonia and Securidaca), or 3-celled (in Monnina and Polygala).

Gynoecium 2 carpelled (usually), or 2–5 carpelled. The pistil (1–)2(–5) celled. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary (1–)2(–5) locular. Gynoecium when G2, median; stylate. Styles 1; apical (often curved and two-lobed, one lobe stigmatic and the other with a tuft of hairs). Stigmas dry type; non-papillate; Group II type. Placentation axile. Ovules in the single cavity when unilocular, 1; when plurilocular, 1 per locule; pendulous; epitropous; with ventral raphe; arillate, or non-arillate; anatropous, or hemianatropous; bitegmic; crassinucellate. Synergids often hooked (and sometimes with filiform apparatus). Hypostase present. Endosperm formation nuclear. Embryogeny asterad.

Fruit fleshy, or non-fleshy; dehiscent, or indehiscent; a capsule, or a drupe, or a nut, or a samara. Capsules loculicidal. Seeds endospermic, or non-endospermic. Endosperm oily. Cotyledons 2; planoconvex. Embryo chlorophyllous (2 species of Polygala); straight.

Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, phytochemistry. C3. C3 physiology recorded directly in Polygala. Anatomy non-C4 type (Polygala). Sugars transported as sucrose (in Polygala). Not cyanogenic. Alkaloids present (commonly), or absent. Iridoids not detected. Saponins/sapogenins present (often), or absent. Proanthocyanidins absent. Flavonols present; kaempferol, or quercetin, or kaempferol and quercetin. Ellagic acid absent (4 Polygala species). Aluminium accumulation demonstrated, or not found.

Geography, cytology. Temperate to tropical. Cosmopolitan, except for New Zealand, Polynesia and frigid zones. X = 5–11(+).

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rutiflorae; Polygalales. Cronquist’s Subclass Rosidae; Polygalales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; fabid; Order Fabales.

Species 800. Genera 17; Atroxima, Balgoya, Barnhartia, Bredemeyera, Carpolobia, Comesperma, Diclidanthera, Epirixanthes, Eriandra, Monnina, Monrosia, Moutabea, Muraltia, Nylandtia, Polygala, Salomonia, Securidaca.

Illustrations. • Technical details: Securidaca (Thonner). • Technical details: Polygala. • Technical details: Polygala (Goebel). • Technical details: Polygala (Lindley). • Polygala vulgaris and P. serpyllifolia (as P. depressa): Eng. Bot. 186 abd 187, 1864. • Polygala vulgaris (B. Ent.). • Polygala chamaebuxus: Bot. Mag. 316, 1795. • Polygala oppositifolia: Bot. Mag. 492, 1800. • Polygala virgata: inflorescence (photo). • Polygala virgata: flower detail (photo). • Muraltia heisteria: Bot. Mag. 340, 1796. • Polygala wallichiana, Salomonia ciliata (as obovata) and S. cordata).

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.’.