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); bearing essential oils, or without essential oils. Switch-plants (sometimes), or ‘normal’ plants; sometimes with the principal photosynthesizing function transferred to stems. Autotrophic, or partially parasitic (Salomonia). When parasitic, on roots of the host. With neither basal nor terminal 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; not peltate. 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. Leaves without a persistent basal meristem.

Leaf anatomy. Stomata anomocytic (usually), or paracytic.

Lamina with secretory cavities (Polygala erioptera), or without secretory cavities. Secretory cavities when present, containing oil; Secretory cavities lysigenous. Minor leaf veins without phloem transfer cells (Polygala).

Stem anatomy. Cork cambium present; initially superficial. Nodes unilacunar. Primary vascular tissue in a cylinder, without separate bundles. Internal phloem absent. Secondary thickening developing from a conventional cambial ring, or anomalous (commonly); commonly via concentric cambia. ‘Included’ phloem present (commonly), or absent. Xylem with tracheids (e.g.Diclidantheraceae), or without tracheids; with fibre tracheids (Securidaca), or without fibre tracheids; with vessels. Vessel end-walls simple. Wood parenchyma paratracheal (predominantly, in Polygaleae), or apotracheal (in Moutabeae).

Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite. Entomophilous. Pollination 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 terminal inflorescence unit cymose. Inflorescences spikes, racemes or panicles, the pedicels often articulated. 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; anisomerous (usually). Calyx 5 (the two inner (posterior-lateral) members often large and petaloid); 1 whorled; polysepalous (usually), or partially gamosepalous (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), 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, or 3-celled.

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

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 (1998) Eudicot; core Eudicot; Rosid; Eurosid I; Fabales. Species 800. Genera 17; Atroxima, Balgoya, Barnhartia, Bredemeyera, Carpolobia, Comesperma, Diclidanthera, Epirixanthes, Eriandra, Monnina, Monrosia, Moutabea, Muraltia, Nylandtia, Polygala, Salmonia, Securidaca.

Illustrations. • Polygala vulgaris. • Technical details (Securidaca). • Technical details (Polygala). • Technical details (Polygala). • Technical details (Polygala).

Cite this publication as: L. Watson and M. J. Dallwitz (1992 onwards). The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 14th December 2000. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993, 1995, 2000), and Watson and Dallwitz (1991) should also be cited (see References).