Including Oceanopapaveraceae auct.(?), Sparmanniaceae J.G. Agardh
Excluding Elaeocarpaceae
Habit and leaf form. Trees and shrubs, or herbs (rarely); non-laticiferous and without coloured juice; leptocaul. Mesophytic. Leaves alternate; spiral, or distichous (or two ranked on the upper half of the shoot); petiolate; non-sheathing; simple. Lamina dissected, or entire; conspicuously asymmetric (commonly), or not conspicuously asymmetric; when dissected, palmately lobed; usually palmately veined. Leaves stipulate. Stipules intrapetiolar; free of one another; caducous (often), or persistent. Leaves without a persistent basal meristem. Domatia recorded (9 genera); represented by hair tufts (nearly always), or pockets (rarely).
Leaf anatomy. Mucilaginous epidermis present, or absent. Stomata present; anomocytic.
Lamina dorsiventral, or isobilateral; with secretory cavities, or without secretory cavities. Secretory cavities containing mucilage. The mesophyll containing mucilage cells. Minor leaf veins without phloem transfer cells (Entelea, Sparmannia).
Stem anatomy. Cork cambium present; initially superficial. Nodes tri-lacunar. 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 libriform fibres; with vessels. Vessel end-walls simple. Vessels without vestured pits. Tile cells present (Durio and Pterospermum types). Wood storied, or partially storied (VPI); parenchyma apotracheal, or paratracheal. Sieve-tube plastids S-type.
Reproductive type, pollination. Hermaphrodite, or monoecious, or polygamomonoecious.
Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in `inflorescences' (sometimes paired); in cymes. The terminal inflorescence unit cymose. Inflorescences cymes, often very complex. Flowers regular; (3-)5 merous; cyclic, or partially acyclic. Sometimes the androecium acyclic. Floral receptacle developing an androphore, or with neither androphore nor gynophore. Free hypanthium absent. Hypogynous disk absent.
Perianth with distinct calyx and corolla, or sepaline (corolla rarely lacking); (4-)5-10; 2 whorled (usually), or 1 whorled; isomerous (usually). Calyx (3-)5; 1 whorled; polysepalous, or gamosepalous (sometimes basally connate); regular; imbricate. Epicalyx present, or absent. Corolla normally (4-)5; 1 whorled; polypetalous; imbricate, or contorted; regular. Petals deeply bifid, or entire.
Androecium (10-)15-100 (usually `many'). Androecial members branched; maturing centrifugally; free of the perianth (inserted at the base of the petals, or on an androphore); free of one another, or coherent; when coherent 1 - adelphous, or 5 - adelphous, or 10 - adelphous; 1-10 - whorled (or acyclic and covering an androphore). Androecium exclusively of fertile stamens, or including staminodes. Staminodes when present, 5-15 (?); non-petaloid. Stamens (10-)15-100 (usually `many'); diplostemonous (rarely), or triplostemonous to polystemonous. Anthers dehiscing via pores, or dehiscing via short slits, or dehiscing via longitudinal slits; bilocular (by contrast with Malvaceae); bisporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral. Anther wall initially with one middle layer, or initially with more than one middle layer (1 or 2); of the `basic' type. Tapetum glandular. Pollen grains aperturate; (2-)3-4 - aperturate, or 6 - aperturate; porate (3-4), or colporate (most commonly tricolporate), or foraminate (oligo-), or rugate (6-); 2-celled.
Gynoecium 2-100 (to `many'). Carpels isomerous with the perianth, or reduced in number relative to the perianth, or increased in number relative to the perianth. Gynoecium syncarpous; eu-syncarpous; superior, or inferior (Neotessmannia). Ovary 1 locular (the septa incomplete), or 2-100 locular (to `many'). Gynoecium stylate. Styles 1; apical. Stigmas 1; capitate (or lobed); dry type; papillate; Group II type. Placentation when unilocular (i.e. rarely), free central; usually axile. Ovules in the single cavity when unilocular, 2-100 (to `many'); (1-)2-50 per locule (to `many'); ascending (usually), or pendulous; with ventral raphe, or with lateral raphe; arillate (sometimes), or non-arillate; hemianatropous to anatropous; bitegmic; crassinucellate. Outer integument contributing to the micropyle, or not contributing to the micropyle. Endothelium differentiated. Embryo-sac development Polygonum-type. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids hooked (or very elongated). Endosperm formation nuclear. Embryogeny onagrad, or asterad.
Fruit fleshy, or non-fleshy; dehiscent, or indehiscent, or a schizocarp. Seeds endospermic. Endosperm oily. Cotyledons 2. Embryo chlorophyllous (4/8); straight, or bent. Micropyle zigzag.
Seedling. Germination phanerocotylar.
Physiology, biochemistry. Not cyanogenic. Alkaloids present (rarely), or absent. Iridoids absent. Proanthocyanidins present; cyanidin. Flavonols present, or absent; kaempferol, or kaempferol and quercetin. Ellagic acid absent (4 species, 4 genera). Arbutin absent. Aluminium accumulation not found. Sugars transported as oligosaccharides + sucrose. C3. C3 recorded in Corchorus, Tilia.
Geography, cytology. Temperate to tropical. Cosmopolitan, except for frigid regions. X = 7-41.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren's Superorder Malviflorae; Malvales. Cronquist's Subclass Dilleniidae; Malvales. Takhtajan's Subclass Dilleniidae; Malvanae; Malvales. Species 450. Genera about 50; Ancistrocarpus, Apeiba, Asterophorum, Berrya, Brownlowia, Burretiodendron, Christiana, Clappertonia, Colona, Corchorus, Craigia, Desplatsia, Diplodiscus, Duboscia, Eleutherostylis, Entelea, Erinocarpus, Glyphaea, Goethalsia, Grewia, Hainania, Heliocarpus, Hydrogaster, Jarandersonia, Luehea, Lueheopsis, Microcos, Mollia, Mortoniodendron, Neotessmannia, Oceanopapaver, Pentace, Pentaplaris, Pseudocorchorus, Schoutenia, Sicrea, Sparmannia, Tahitia, Tetralix, Tilia, Trichospermum, Triumfetta, Vasivaea, Vinticena.
Economic uses, etc. Tilia supplies lumber (basswood, whitewood), also ornamental and shade trees popular for street plantings.
Illustrations. tilia289.gif tilia371.gif
