The families of flowering plants.
IncludingCassipoureaceae J.G. Agardh, Hirtellaceae Horan. (p.p.), Legnotidae (Legnotidaceae) Endl., Macarisiaceae J.G. Agardh corr. Bullock, Macharisieae (Macharisiaceae) J.G. Agardh, Paletuvieraceae Lam. ex KuntzeExcluding Anisophylleaceae
Habit and leaf form. Trees, or shrubs (often mangroves). Helophytic. Leaves opposite (but not decussate), or whorled (Weihea); of Weihea 3 per whorl; leathery; petiolate; simple. Lamina entire; pinnately veined. Leaves stipulate.Stipules interpetiolar (sheathing the terminal bud); with colleters (inside at the base); caducous. Lamina margins entire, or crenate, or dentate.
Leaf anatomy. Mucilaginous epidermis present, or absent. Stomata anomocytic.
The mesophyll with sclerencymatous idioblasts, or without sclerenchymatous idioblasts. Minor leaf veins without phloem transfer cells (Rhizophora).
Stem anatomy. Cork cambium present; initially superficial. Nodes tri-lacunar. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent. Xylem with tracheids; with vessels. Vessel end-walls scalariform, or simple, or scalariform and simple. Vessels without vestured pits. Wood parenchyma apotracheal, or paratracheal.
Reproductive type, pollination. Plants hermaphrodite, or polygamomonoecious (rarely); viviparous (in mangrove species), or not viviparous. Pollination mechanism conspicuously specialized (exhibiting explosive pollen release and specialised stamen-petal arangements), or unspecialized.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’, or solitary (rarely); when solitary, axillary; when aggregated, in cymes, or in racemes, or in fascicles. The ultimate inflorescence unit cymose. Inflorescences axillary. Flowers regular; (3–)4–6(–20) merous. Free hypanthium present (the hypanthium sometimes prolonged beyond the ovary), or absent. Hypogynous disk present (in hypogynous flowers), or absent; when present, intrastaminal.
Perianthwith distinct calyx and corolla; 6–32; 2 whorled; isomerous. Calyx (3–)4–5(–16); 1 whorled; polysepalous; regular; commonly fleshy (or leathery); persistent; valvate. Corolla (3–)4–5(–16); 1 whorled; appendiculate (usually with both a terminal arista and filiform appendages on the lobes), or not appendiculate; polypetalous (the petals often shorter than the sepals); contorted (or infolded); commonly fleshy. Petals clawed, or sessile; deeply bifid, or bilobed, or fringed (lacerate), or entire.
Androecium 8–40. Androecial members branched, or unbranched; free of the perianth (generally inserted on the outer edge of the perigynous or epigynous disk); free of one another, or coherent (then with the filaments basally connate); generally 1 whorled (but sometimes doubtfully?). The androecial bundles when stamens bundled, opposite the corolla members (with each petal individually enclosing 1–5 stamens, cf. Rhamnaceae). Androecium exclusively of fertile stamens. Stamens 8–40; diplostemonous (often paired opposite the petals), or triplostemonous to polystemonous; filantherous, or with sessile anthers. Filaments appendiculate, or not appendiculate. Anthers introrse; bilocular, or four locular to many locular (cross partitioned, in Rhizophora); tetrasporangiate. Pollen grains aperturate; 3(–4) aperturate; colporate (to colporoidate, sometimes zonorate); 2-celled (in 3 genera).
Gynoecium 2–5(–20) carpelled (multicarpellate in Crossostylis). Carpels reduced in number relative to the perianth, or isomerous with the perianth, or increased in number relative to the perianth (?). The pistil 1–6(–20) celled. Gynoecium syncarpous; eu-syncarpous; superior to inferior. Ovary 1 locular (by failure to partition), or 2–5(–20) locular. Locules without ‘false septa’. Gynoecium when G2, median. Epigynous disk of perigynous flowers, present, or absent. Gynoecium stylate. Styles 1; apical. Stigmas 1 (shallowly to clearly lobed); lobed or capitate; generally papillate. Placentation when unilocular, apical; usually axile to apical. Ovules 2 per locule (usually), or 3–25 per locule (8–25 in Pellacalyx); pendulous; epitropous; with ventral raphe; arillate, or non-arillate; hemianatropous, or anatropous; 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 (uninucleate); not proliferating. Synergids pear-shaped. Endosperm formation nuclear. Endosperm haustoria present; chalazal (at least in Ceriops).
Fruit fleshy (usually), or non-fleshy; dehiscent (when dry), or indehiscent; a capsule (rarely), or a berry, or a drupe. Seeds copiously endospermic. Endosperm oily (and fleshy). Seeds winged, or wingless. Embryo well differentiated. Cotyledons 2(–4). Embryo chlorophyllous; straight. Micropylezigzag.
Seedling.Germination phanerocotylar (or viviparous).
Physiology, biochemistry. Not cyanogenic. Alkaloids present, or absent. Iridoids not detected. Proanthocyanidins present; cyanidin, or delphinidin. Flavonols present; quercetin, or kaempferol and quercetin. Ellagic acid present (Cassipourea), or absent (Rhizophora). Saponins/sapogenins absent. Anatomy non-C4 type (Bruguiera, Ceriops, Pellacalyx, Rhizophora).
Geography, cytology. Sub-tropical to tropical. Pantropical and subtropical, concentrated in the Old World. X = 8, 9.
Taxonomy.Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Myrtiflorae; Rhizophorales. Cronquist’s Subclass Rosidae; Rhizophorales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; fabid; Order Malpighiales.
Species 120. Genera 15; Anopyxis, Blepharistemma, Bruguiera, Carallia,Cassipourea, Ceriops, Comiphyton, Crossostylis, Dactylopetalum,Gynotroches, Kandelia, Macarisia, Pellacalyx, Rhizophora,Sterigmapetalum, Weihea (= Cassipourea).
General remarks. Juncosa and Tomlinson (1988) present a taxonomic synopsis.
Economic uses, etc. Some yield wood used for underwater construction and piling, and tannins are obtained from the bark.