Family Dipterocarpaceae

Dipterocarpaceae Bl.

Including Monotaceae (E. Gilg) Maury ex Takhtajan

Habit and leaf form. Trees (often tall with buttressed bases, constituting the ‘mixed Dipterocarp’ forests dominant in Asian lowland rainforests); non-laticiferous and without coloured juice; resinous (Dipterocarpoideae), or not resinous; leptocaul. Mesophytic. Leaves evergreen; alternate; leathery; petiolate (the petiole often geniculate or sinuate); simple. Lamina entire; usually prominently pinnately veined; cross-venulate. Leaves stipulate. Stipules intrapetiolar; free of one another; caducous, or persistent. Lamina margins entire. Domatia occurring in the family (from 4 genera and numerous species); manifested as pits (all).

Leaf anatomy. Mucilaginous epidermis present, or absent.

Lamina dorsiventral. The mesophyll containing mucilage cells, or not containing mucilage cells.

Stem anatomy. Secretory cavities present; with resin, or with mucilage. Cork cambium present; initially superficial. Nodes tri-lacunar, or penta-lacunar. Cortical bundles present, or absent. Medullary bundles absent. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones. ‘Included’ phloem absent. Xylem with fibre tracheids; with vessels. Vessel end-walls horizontal; simple. Vessels consistently with vestured pits. Wood parenchyma apotracheal, or paratracheal.

Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite. Pollination entomophilous.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes (rarely), or in racemes, or in panicles (usually). Inflorescences terminal, or axillary. Flowers bracteate (the bracts caducous); large (showy); often fragrant; regular; 5 merous; cyclic, or partially acyclic. Sometimes the androecium acyclic (the stamens then somewhat irregularly disposed). Floral receptacle developing an androphore (Monotoideae), or with neither androphore nor gynophore (Dipterocarpoideae).

Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; polysepalous, or gamosepalous (frequently with a short or long tube); blunt-lobed. Calyx lobes markedly shorter than the tube to markedly longer than the tube. Calyx regular; persistent; accrescent (some or all of the sepals becoming enlarged to constitute a winged fruit); imbricate, or valvate. Corolla 5; 1 whorled; polypetalous, or gamopetalous (the petals often connate at the base). Corolla lobes markedly longer than the tube. Corolla contorted (spirally twisted in bud).

Androecium (5–)15(–100). Androecial members branched (typically with 10 trunk bundles); when many, maturing centrifugally; adnate (often, to the base of the corolla), or free of the perianth; free of one another, or coherent (usually, the filaments connate below); 1–3 whorled (or irregularly disposed). Androecium exclusively of fertile stamens. Stamens (5–)15(–100); isomerous with the perianth to polystemonous. Anthers dorsifixed (Monotoideae), or basifixed (Dipterocarpoideae); dehiscing via longitudinal slits; tetrasporangiate; usually appendaged. The anther appendages apical (the connective extended into a sterile tip to the anther). Endothecium not developing fibrous thickenings. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or decussate. Anther wall initially with more than one middle layer; of the ‘dicot’ type. Tapetum glandular. Pollen grains aperturate; 3 aperturate; colpate, or colporate; 2-celled.

Gynoecium 2–3(–5) carpelled. Carpels reduced in number relative to the perianth to isomerous with the perianth. The pistil 2–3(–5) celled. Gynoecium syncarpous; synovarious, or synstylovarious; superior, or partly inferior (Anisoptera). Ovary 2–3(–5) locular. Gynoecium stylate. Styles 1, or 3; when 3, free to partially joined; apical. Stigmas 3 lobed, or 6 lobed. Placentation axile to apical. Ovules 2–4 per locule; pendulous (or laterally attached); more or less epitropous; with ventral raphe; anatropous; bitegmic; crassinucellate. Outer integument not contributing to the micropyle. Embryo-sac development Polygonum-type. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids hooked. Endosperm formation nuclear. Embryogeny asterad (or by irregular cleavage).

Fruit non-fleshy; tardily dehiscent, or indehiscent (usually); commonly conspicuously winged by the accrescent calyx, capsular-indehiscent, or a capsule, or a nut (usually). Capsules when capsular/dehiscent, splitting irregularly, or valvular (then the pericarp splitting into three valves). Fruit 1 seeded. Cotyledons 2. Embryo chlorophyllous (5/6).

Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, biochemistry. Not cyanogenic. Alkaloids absent (?). Iridoids not detected. Arthroquinones detected (Vatica); polyacetate derived. Proanthocyanidins present, or absent; when present, cyanidin and delphinidin. Flavonols present, or absent; kaempferol, or myricetin, or quercetin and myricetin, or kaempferol, quercetin, and myricetin. Ellagic acid present (6 genera, 8 species), or absent (3 genera, 3 species). Ursolic acid present. Saponins/sapogenins absent. Aluminium accumulation not found.

Geography, cytology. Paleotropical (mostly), or Neotropical (Pakaraimaea). Tropical. Palaeotropical, chiefly Indomalayan. X = 6, 7, 10, 11.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Malviflorae; Malvales. Cronquist’s Subclass Dilleniidae; Theales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order Malvales.

Species 580. Genera 16; Marquesia and Monotes (Africa); Anisoptera, Cotylelobium, Dipterocarpus, Dryobalanops, Hopea, Neobalanocarpus, Parashorea, Shorea, Stemonoporus, Upuna, Vateria, Vatica (Indomalayan); Pakaraimaea (Guayana).

Illustrations.
• Technical details: Dipterocarpus, Dryobalanops (Lindley).