Staurogyne Wall.

Scientific Description

Family Acanthaceae.

Habit and leaf form. Herbs, or shrubs (undershrubs, without cystoliths). The herbs annual to perennial. Young stems cylindrical. Hydrophytic, or helophytic, or mesophytic, or xerophytic. Leaves opposite, or alternate and opposite (then uppermost alternate); petiolate to sessile; gland-dotted, or not gland-dotted; simple. Leaf blades entire; flat; pinnately veined, or palmately veined; cross-venulate. Leaves without stipules. Leaf blade margins entire, or dentate. Stem anatomy. Nodes unilacunar. Secondary thickening developing from a conventional cambial ring. Roots. Aerial roots present, or absent.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous. Pollination mechanism conspicuously specialized, or unspecialized.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in racemes, or in spikes. The terminal inflorescence unit cymose, or racemose. Inflorescences terminal, or axillary. Flowers bracteate. Bracts intergrading with leaves, spirally arranged, smaller higher up. Flowers bi- bracteolate. Bracteoles similar in length to calyx lobes. Flowers somewhat irregular to very irregular, or regular; zygomorphic. The floral asymmetry involving the perianth and involving the androecium. Flowers 5 merous; tetracyclic. Free hypanthium absent. Hypogynous disk present. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx 5; 1 -whorled; gamosepalous; lobed; regular, or unequal but not bilabiate (then one lobe larger than other 4); with the median member posterior. Corolla 5; 1 -whorled; gamopetalous; in bud with 2 lobes enclosing the other 3; more or less regular, or bilabiate. Androecium 4(–5). Androecial members adnate; markedly unequal; free of one another, or coherent; 1 -whorled. Androecium exclusively of fertile stamens, or including staminodes. Staminodes when present, 1. Stamens 4; remaining included (usually), or becoming exserted; didynamous; reduced in number relative to the adjacent perianth; oppositisepalous; all alternating with the corolla members. Anthers dorsifixed; dehiscing via longitudinal slits; bilocular; tetrasporangiate; appendaged (? sometimes shortly mucronate at base), or unappendaged. Pollen shed as single grains. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary plurilocular; 2 locular. Gynoecium median. Ovary sessile. Styles 1; attenuate from the ovary; apical; much longer than the ovary at anthesis. Stigmas 1; 2 - lobed (lobes sometimes unequal, entire or forked); wet type, or dry type; papillate, or non-papillate; Group II type, or Group III type. Placentation axile. Ovules 20–50 per locule (i.e., 20 to many); in 2–4 rows in each locule; non-arillate, or arillate; hemianatropous, or anatropous, or campylotropous.

Fruit and seed features. Fruit non-fleshy; dehiscent; a capsule (ellipsoid, seed-bearing throughout length). Capsules loculicidal. Fruit elastically dehiscent. Dispersal unit the seed. Fruit 50–80 seeded. Seeds globular or ellipsoid; endospermic; not conspicuously hairy. Embryo well differentiated. Cotyledons 2. Embryo achlorophyllous; curved. Testa reticulately ribbed or foveolate. Seedling. Germination phanerocotylar.

Physiology, biochemistry. Aluminium accumulation not found.

Special features. The funicles not as in Acanthaceae.

Geography, cytology, number of species. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, Northern Territory, and Queensland. Northern Botanical Province.

Additional characters Fruit erostrate. Pollen grains colpate.