Family Turneraceae
Turneraceae DC.~ Passifloraceae s. l. Habit and leaf form. Trees (rarely), or shrubs, or herbs. Plants non-succulent. Leaves alternate; spiral; petiolate; simple. Lamina dissected, or entire; when dissected, pinnatifid; pinnately veined; cross-venulate. Leaves stipulate (Erblichia), or exstipulate (usually, but often with a pair of glands or extrafloral nectaries at the base of the blade). Stipules and/or prophylls and leaf primordia with colleters. Lamina margins serrate, or dentate (the teeth sometimes glandular). Leaf anatomy. Mucilaginous epidermis present, or absent. Stomata paracytic (usually, mostly), or anomocytic and anisocytic. Lamina dorsiventral, or isobilateral. The mesophyll with sclerencymatous idioblasts, or without sclerenchymatous idioblasts; containing calcium oxalate crystals. The mesophyll crystals druses. Minor leaf veins without phloem transfer cells (Turnera). Stem anatomy. Cortical bundles present, or absent. Secondary thickening developing from a conventional cambial ring (?). Xylem with libriform fibres. Vessel end-walls simple, or scalariform and simple. Wood parenchyma apotracheal. Reproductive type, pollination. Plants hermaphrodite; heterostylous. Pollination self-pollinated or entomophilous. Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; when solitary, axillary; when aggregated, in racemes. Inflorescences terminal, or axillary, or epiphyllous (10 species of Turnera). Flowers often (bi-) bracteolate; regular; 5 merous; cyclic; tetracyclic. Free hypanthium present (short to tubular). Perianth with distinct calyx and corolla (and sometimes with a membranous corona, inserted below the throat of the calyx or at the base of the sepals); 10; 2 whorled; isomerous. Calyx 5; 1 whorled; gamosepalous; toothed; regular (usually with a hemispherical swelling inside); not persistent; imbricate. Corolla 5; 1 whorled; polypetalous; contorted; regular; yellow, or red; deciduous. Petals clawed. Androecium 5. Androecial members free of the perianth (inserted low in the hypanthium); free of one another; 1 whorled. Androecium exclusively of fertile stamens (but the hypanthium often provided with five extrastaminal glands or protuberances, or (Piriquetia, Erblichia) with a narrow, fringed corona). Stamens 5; isomerous with the perianth; oppositisepalous; alternating with the corolla members. Anthers dehiscing via longitudinal slits; introrse. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. Anther wall initially with more than one middle layer (2). Tapetum glandular. Pollen shed as single grains. Pollen grains aperturate; 3 aperturate; colporate (or colporoidate); 2-celled. Gynoecium 3 carpelled. Carpels reduced in number relative to the perianth. The pistil 1 celled. Gynoecium syncarpous; synovarious; superior to partly inferior. Ovary 1 locular; sessile. Gynoecium stylate. Styles 3 (opposite the placentas); free. Stigmas 3 (fringed); commissural (assuming ’opposite the placentas‘ means aligned with them); dry type; non-papillate; Group II type (a). Placentation parietal. Ovules in the single cavity (3–)25–100 (to ‘many’); funicled; ascending; arillate (with an ostensibly funicular aril); anatropous; bitegmic; crassinucellate. Outer integument contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids hooked. Endosperm formation nuclear. Embryogeny onagrad. Fruit non-fleshy; dehiscent; a capsule. Capsules valvular (each of the three valves with a median placenta). Seeds copiously endospermic. Endosperm oily. Embryo well differentiated. Cotyledons 2; planoconvex. Embryo straight. Seedling. Germination phanerocotylar. Physiology, biochemistry. Cyanogenic (often), or not cyanogenic. Cynogenic constituents of the gynocardin group (?). Alkaloids present, or absent. Proanthocyanidins absent. Flavonols absent. Ellagic acid absent. Geography, cytology. Mainly sub-tropical to tropical (a few warm temperate). Tropical and South Africa, Madagascar, Mascarenes, Central and tropical South America, West Indies. X = 7, 10. Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Violiflorae; Violales. Cronquist’s Subclass Dilleniidae; Violales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; fabid; Order Malpighiales (as a synonym of Passifloraceae?). Species 120. Genera 10; Adenoa, Erblichia, Hyalocalyx, Loewia, Mathurina, Piriqueta, Stapfiella, Streptopetalum, Tricliceras (Wormskioldia), Tunera (with half the species). Illustrations. |
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