Family Tropaeolaceae
Tropaeolaceae DC.Including Cardamindeae (Cardamindaceae) Link Habit and leaf form. Herbs (with mustard oils and watery juice); not resinous. Plants somewhat succulent, or non-succulent. Annual to perennial; with neither basal nor terminal aggregations of leaves; when perennial, tuberous. Prostrate or climbing; often petiole twiners. Leaves alternate, or alternate and opposite (sometimes opposite below); flat; petiolate (the petioles often long and twining); non-sheathing; gland-dotted, or not gland-dotted; simple, or compound; peltate; when compound, palmate. Lamina when simple entire, or dissected; when simple/dissected, palmatifid; palmately veined; cross-venulate. Leaves stipulate, or exstipulate; without a persistent basal meristem. Leaf anatomy. Mucilaginous epidermis present, or absent. Stomata present; mainly confined to one surface, or on both surfaces; anomocytic. Minor leaf veins without phloem transfer cells (Tropaeolum). Stem anatomy. Cork cambium present, or absent; initially deep-seated. Nodes tri-lacunar. Primary vascular tissue comprising a ring of bundles. Secondary thickening absent, or developing from a conventional cambial ring. Xylem with vessels. Vessel end-walls simple. Vessels without vestured pits. Reproductive type, pollination. Plants hermaphrodite. Pollination entomophilous; mechanism conspicuously specialized (in T. majus, the the anthers move sequentially to the nectariferous spur to shed their pollen before returning to their original positions, when the style moves to the spur. The hairs on the lower margins of the anterior petals exclude the entry of insects too small to effect pollination). Inflorescence, floral, fruit and seed morphology. Flowers solitary; axillary; medium-sized (showy); very irregular (usually), or somewhat irregular (Tropaeastrum); zygomorphic. The floral irregularity involving the perianth and involving the androecium. Flowers cyclic; pentacyclic. Free hypanthium present (the corolla slightly perigynous). Perianth with distinct calyx and corolla; 7–10; 2 whorled; isomerous, or anisomerous (the corolla sometimes incomplete); petaloid. Calyx 5 (the sepals petaloid); 1 whorled; gamosepalous; 5 blunt-lobed; bilabiate; long to short spurred (from below the dorsal (adaxial) sepal(s)); imbricate, or valvate; with the median member posterior. Corolla 2–5 (the two upper members exterior and often differing from the lower, which are sometimes missing); 1 whorled; polypetalous; imbricate. Petals clawed; variously lobed or fringed. Androecium 8. Androecial members free of the perianth; markedly unequal (declinate); free of one another; 2 whorled (four per whorl, the median of each supposedly suppressed). Androecium exclusively of fertile stamens. Stamens 8; filantherous (the filaments filiform). Anthers basifixed; dehiscing via longitudinal slits; latrorse; tetrasporangiate. Pollen grains aperturate; 2–3 aperturate; colporate (the colpi short); 2-celled. Gynoecium 3 carpelled; partly petaloid (sometimes with petaloid modification of style and/or stigma), or non-petaloid. Carpels reduced in number relative to the perianth to increased in number relative to the perianth. The pistil 3 celled. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary 3 locular. Gynoecium oblique; stylate. Styles 1; apical. Stigmas 1, or 3; 3 lobed; dry type; non-papillate. Placentation axile to apical. Ovules 1 per locule; pendulous; epitropous; with ventral raphe; non-arillate; anatropous; bitegmic; tenuinucellate. Outer integument not contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids pear-shaped. Endosperm formation nuclear. Embryogeny solanad. Fruit fleshy (sometimes), or non-fleshy; a schizocarp. Mericarps 1 (Magallana), or 3; comprising nutlets, or comprising drupelets, or samaroid (Magallana). Dispersal unit the mericarp. Seeds non-endospermic; with amyloid. Embryo well differentiated. Cotyledons 2; thick, plano-convex. Embryo chlorophyllous (Tropaeolum majus); straight. Seedling. Germination cryptocotylar. Physiology, biochemistry. Mustard-oils present. Not cyanogenic. Iridoids not detected. Proanthocyanidins absent. Flavonols present; kaempferol and quercetin. Ellagic acid absent. Arbutin absent. C3. C3 physiology recorded directly in Tropaeolum. Geography, cytology. Neotropical. Temperate to tropical. Mexico to temperate South America, widely introduced elsewhere. X = 12–14. Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rutiflorae; Tropaeolales. Cronquist’s Subclass Rosidae; Geraniales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order Brassicales. Species 92. Genera 3; Magallana, Tropaeastrum, Tropaeolum. Illustrations. |
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