Ixora L.

Scientific Description

Family Rubiaceae.

Habit and leaf form. Small trees, or shrubs; evergreen. Young stems tetragonal. Helophytic, or mesophytic, or xerophytic. Leaves opposite, or whorled (rarely); 3 per whorl; leathery (to chartaceous); petiolate to sessile; connate (via the stipules), or not connate; gland-dotted, or not gland-dotted; simple; epulvinate. Leaf blades entire; one-veined, or pinnately veined; cross-venulate. Leaves with stipules. Stipules interpetiolar (with a truncate to triangular limb, usually connate for most of the length, bearing a short or long cuspidate or aristate lobe, rarely pubescent inside); with colleters (secreting mucilage), or without colleters. Leaf blade margins entire, or serrate. Leaves without a persistent basal meristem. Domatia not recorded (absent). Leaf anatomy. Hairs present, or absent. Stem anatomy. Nodes unilacunar, or tri-lacunar. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite (protandrous). 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’; often 3 together, in cymes, or in heads, or in corymbs, or in panicles. The terminal inflorescence unit cymose. Inflorescences terminal, or axillary, or cauliflorous; bracts at base of inflorescence free. Flowers pedicellate to sessile; bracteate (stipule-like); bracteolate, or ebracteolate; small to large; usually fragrant; regular; 4 merous, or 5 merous; cyclic; tetracyclic. Free hypanthium present, or absent (depending on interpretation). Perianth with distinct calyx and corolla; 8, or 10; 2 -whorled; the two whorls isomerous. Calyx 4, or 5; 1 -whorled; gamosepalous; entire, or lobed; hairy, or glabrous; open in bud; tube ovoid; regular; persistent. Corolla 4, or 5; 1 -whorled; gamopetalous. Corolla lobes markedly shorter than the tube, or about the same length as the tube (occasionally). Corolla contorted (to the left); tubular (or salver-shaped); regular; glabrous abaxially, or hairy abaxially (rarely pilose); glabrous adaxially, or hairy adaxially (sometimes bearded at throat); white, or yellow, or pink, or red. Androecium 4, or 5. Androecial members adnate (to the corolla tube); free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 4, or 5. Staminal insertion in the throat of the corolla tube. Stamens becoming exserted (and erect or spreading in mature flowers); isomerous with the perianth; oppositisepalous; filantherous (filaments very short). Anthers linear; attached near the base or dorsifixed around middle; dehiscing via longitudinal slits; twisted when dehisced; tetrasporangiate; appendaged; apiculate. Pollen shed as single grains. Gynoecium 2 carpelled, or 3 carpelled. The pistil 2 celled, or 3 celled. Carpels reduced in number relative to the perianth. Gynoecium syncarpous; synstylovarious to eu-syncarpous; inferior. Ovary plurilocular; 2 locular, or 3 locular. Gynoecium transverse. Epigynous disk present (disc annular, fleshy). 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 (equalling or slightly exceeding the corolla tube, stigma exserted); hairy, or hairless. Stigmas 1; 2 - lobed (lobes recurved); wet type, or dry type; papillate, or non-papillate; Group II type and Group IV type. Placentation attachment near the top of the septum, placenta fleshy. Ovules 1 per locule (ovule immersed in the placenta); pendulous, or horizontal, or ascending; anatropous, or hemianatropous.

Fruit and seed features. Fruit fleshy, or non-fleshy (slightly fleshy or coriaceous); red (usually); indehiscent; a drupe. The drupes with one stone, or with separable pyrenes (then with 2 pyrenes). Fruit 1–2 seeded. Seeds endospermic. Endosperm ruminate, or not ruminate; oily. Cotyledons 2. Embryo curved. Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, biochemistry. Aluminium accumulation not found.

Geography, cytology, number of species. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, Northern Territory, Queensland, and New South Wales. X = 11.

Additional characters Corolla lobes spreading (or reflexing).

Etymology. Said to be named after Iswara or Israra, a Malabar deity, perhaps the god Siva, to whom the flowers of some species are offered.