Family Sonneratiaceae

Sonneratiaceae Engl. & Gilg

Alternatively Blattiaceae~ Lythraceae

Including Duabangaceae Takhtajan

Habit and leaf form. Shrubs, or lianas. Self supporting, or climbing. Helophytic, or mesophytic. Leaves opposite, or whorled; leathery; petiolate, or subsessile; simple. Lamina entire; pinnately veined; cross-venulate. Leaves exstipulate. Lamina margins entire.

Leaf anatomy. The mesophyll with sclerencymatous idioblasts.

Stem anatomy. Cork cambium present; initially superficial. Primary vascular tissue bicollateral. Internal phloem present. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent. Xylem with libriform fibres. Vessel end-walls simple. Vessels with vestured pits.

Reproductive type, pollination. Plants hermaphrodite (usually), or monoecious, or polygamomonoecious (?); homostylous.

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; in cymes, or in corymbs. The ultimate inflorescence unit cymose. Inflorescences terminal; 1–3 flowered cymes or corymbs. Flowers medium-sized to large; regular; cyclic; polycyclic. Free hypanthium present (thick). Hypogynous disk present.

Perianth with distinct calyx and corolla, or sepaline (corolla sometimes lacking); 8–16; 1 whorled, or 2 whorled; isomerous. Calyx 4–8; 1 whorled; gamosepalous, or polysepalous (on the hypanthium, often coloured inside); campanulate; regular; persistent (leathery); valvate. Corolla 4–8 (small); 1 whorled; polypetalous; crumpled in bud; regular.

Androecium (12–)16–100 (usually ‘many’). Androecial members branched, or unbranched; free of the perianth (on the hypanthium); free of one another, or coherent; when cohering, 4–8 adelphous (in clusters opposite the petals); 1–4 whorled (‘in clusters or in several whorls’). Androecium exclusively of fertile stamens. Stamens (12–)16–50; diplostemonous to polystemonous. Anthers dorsifixed; versatile; dehiscing via longitudinal slits; introrse; tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Anther wall initially with more than one middle layer (2 or 3); of the ‘dicot’ type. Tapetum glandular. Pollen grains aperturate; 3 aperturate; porate (Duabanga), or colporate (or colporoidate, Sonneratia); 2-celled.

Gynoecium 4–15 carpelled. Carpels isomerous with the perianth, or increased in number relative to the perianth. The pistil 4–15 celled. Gynoecium syncarpous; eu-syncarpous; superior to partly inferior (on a broad base). Ovary 4–15 locular. Styles 1 (bent in bud); from a depression at the top of the ovary; apical. Stigmas 1; capitate. Placentation axile. Ovules 10–50 per locule (‘many’); funicled; horizontal; 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; very ephemeral. Synergids hooked. Endosperm formation nuclear. Embryogeny onagrad.

Fruit fleshy, or non-fleshy; indehiscent; a capsule, or a berry; 15–100 seeded (‘many’). Seeds non-endospermic. Cotyledons 2. Embryo chlorophyllous (1/1); straight, or curved.

Seedling. Germination phanerocotylar.

Physiology, biochemistry. Alkaloids absent (one species). Arthroquinones detected (Sonneratia); polyacetate derived. Ellagic acid present. Saponins/sapogenins absent. Sugars transported as sucrose (in Duabanga). Anatomy non-C4 type (Sonneretia).

Geography, cytology. Tropical. East tropical Africa and Madfagascar, Southeast Asia and Malaysia, Northern Australia, Western Pacific. Central, East tropical and West tropical Africa, Madagascar, Malay Archipelago, Australasia, and Pacific Islands. X = 9, 18, 24.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Myrtiflorae; Myrtales. Cronquist’s Subclass Rosidae; Myrtales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order Myrtales (as a synonym of Lythraceae).

Species 7. Genera 2; Duabanga, Sonneratia.