Morinda L.

Scientific Description

Family Rubiaceae.

Habit and leaf form. Trees, or shrubs, or lianas. Young stems tetragonal, or cylindrical. Self supporting, or climbing. Helophytic, or mesophytic, or xerophytic. Leaves medium-sized to very large; opposite, or whorled (rarely); 3 per whorl; ‘herbaceous’, or leathery; petiolate; connate (via the stipules), or not connate; gland-dotted, or not gland-dotted; simple; epulvinate. Leaf blades entire; pinnately veined; cross-venulate. Leaves with stipules. Stipules interpetiolar (membranous or scarious, sometimes leafy, free or connate); with colleters (secreting mucilage), or without colleters. Leaf blade margins entire, or serrate. Leaves without a persistent basal meristem. Domatia recorded; represented by pits. Stem anatomy. Nodes unilacunar, or tri-lacunar. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite, or functionally male. Unisexual flowers present, or absent. Plants hermaphrodite, or andromonoecious. Plants homostylous, or heterostylous. Entomophilous. Pollination mechanism conspicuously specialized (with passive pollen presentation involving stylar modification), or unspecialized.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’. Inflorescence few-flowered, or many-flowered. Flowers in cymes, or in heads (heads globular to ovoid, pedunculate). Inflorescences simple, or compound (frequently arranged in umbels). The terminal inflorescence unit cymose. Inflorescences terminal, or axillary, or leaf-opposed. Flowers small to medium-sized; fragrant; regular; 3–7 merous; cyclic; tetracyclic. Free hypanthium present, or absent (depending on interpretation). Perianth with distinct calyx and corolla; 6–14; 2 -whorled; the two whorls isomerous. Calyx 3–7; 1 -whorled; gamosepalous; entire, or lobed (then short-toothed, rarely with 1 or 2 leaf-like lobes); open in bud; regular; persistent. Corolla 3–7; 1 -whorled; gamopetalous; valvate; funnel-shaped, or hypocrateriform; regular; glabrous adaxially, or hairy adaxially (throat pilose); white, or cream, or yellow, or purple. Androecium 4–7. Androecial members adnate (to the corolla tube); free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 4–7. Staminal insertion near the base of the corolla tube, or midway down the corolla tube. Stamens becoming exserted, or remaining included; isomerous with the perianth; oppositisepalous; filantherous (filaments short). Anthers dorsifixed; dehiscing via longitudinal slits; introrse; tetrasporangiate. Pollen shed in aggregates, or shed as single grains; if aggregated, in tetrads. Fertile gynoecium present, or absent (when flower male). Gynoecium 2 carpelled. The pistil 2 celled, or 4 celled. Carpels reduced in number relative to the perianth. Gynoecium syncarpous; synstylovarious to eu-syncarpous; inferior. Ovary plurilocular; 2 locular, or 4 locular (by misinterpretation). Locules secondarily divided by ‘false septa’ (usually), or without ‘false septa’. Gynoecium transverse. Epigynous disk present (disc swollen or annular). Gynoecium stylate. Styles 1; attenuate from the ovary, or from a depression at the top of the ovary; apical; shorter than the ovary at anthesis to much longer than the ovary at anthesis; becoming exserted, or not becoming exserted. Stigmas 1; 2 - lobed, or 3 - lobed (rarely); wet type, or dry type; papillate, or non-papillate; Group II type and Group IV type. Placentation axile. Ovules 2 per locule, or 1 per locule (by misinterpretation of the false septa in the ovary); ascending (attached to the septum below the middle or near the base); anatropous, or amphitropous.

Fruit and seed features. Fruit fleshy (succulent), or non-fleshy; green to yellow, or orange to red; indehiscent; a drupe. The drupes with one stone, or with separable pyrenes (pyrenes 2–4). Gynoecia of adjoining flowers combining to form a multiple fruit (composed of few to numerous connate drupes). Fruit 1–4 seeded. Seeds obovoid or reniform; endospermic. Endosperm fleshy, ruminate, or not ruminate; oily. Seeds winged (a winglike structure extends halfway along the edges or completely surrounds the endosperm). Cotyledons 2. Embryo straight, or curved. Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, biochemistry. Aluminium accumulation demonstrated, or not found.

Geography, cytology, number of species. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, Northern Territory, Queensland, New South Wales, and Victoria.