Murdannia Royle

Scientific Description

Family Commelinaceae.

Habit and leaf form. Herbs; evergreen. Plants non-succulent. Annual, or perennial; plants with a basal concentration of leaves, or with neither basal nor terminal concentrations of leaves. Young stems cylindrical, or oval in section (?); often breaking easily at the nodes. Mesophytic, or helophytic (?). Leaves alternate; spiral, or distichous (?); fleshy, or ‘herbaceous’ (?); petiolate, or sessile (?); sheathing. Leaf sheaths with joined margins. Leaves simple. Leaf blades entire; linear to ovate; parallel-veined. Leaves eligulate. Leaf blade margins entire. Vernation involute, or plicate (?). Vegetative anatomy. Plants with silica bodies, or without silica bodies (?). Leaf anatomy. Leaf blade epidermis without differentiation into ‘long’ and ‘short’ cells. Guard-cells not ‘grass type’. Hairs present, or absent; glandular hairs absent. Stem anatomy. Secondary thickening absent.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Floral nectaries absent (nectaries lacking). Autogamous or entomophilous (but without nectar). Pollination mechanism conspicuously specialized (with dimorphic stamens comprising concolourous fertilizing members, and specialised, bright yellow ‘food stamens’ attractive to pollinators but producing little pollen. Moniliform hairs on the filaments may further delude visitors by simulating pollen).

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’, or solitary (rarely); in cymes. The terminal inflorescence unit cymose. Inflorescences terminal (usually); a panicle with cymose branches, rarely of 1-several flowers; without involucral bracts. Flowers pedicellate; regular (usually), or very irregular. The floral asymmetry when present, involving the perianth. Flowers cyclic. Perigone tube absent. Perianth with distinct calyx and corolla; 6; 2 -whorled; isomerous; free, or joined (?); sepaloid and petaloid; different in the two whorls; blue, or purple, or white. Calyx 3; 1 -whorled; polysepalous, or gamosepalous (?); regular (segments equal or nearly so). Corolla 3; 1 -whorled; polypetalous; regular (usually), or unequal but not bilabiate (sometimes with one petal reduced); blue to purple, or white. Petals clawed. Androecium 6 (usually), or 2–3 (when staminodes absent). Androecial members free of the perianth; free of one another, or coherent (then some filament bases connate); 2 -whorled. Androecium including staminodes, or exclusively of fertile stamens (rarely). Staminodes 3(–4); with hastate or 3-lobed sterile anthers. Stamens (2–)3; reduced in number relative to the adjacent perianth, or isomerous with the perianth. Filaments hairy, or glabrous. Anthers dorsifixed, or basifixed (?); versatile, or non-versatile (?); dehiscing via longitudinal slits; appendaged, or unappendaged (?). Gynoecium 3 carpelled. The pistil 2–3 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary plurilocular; 2–3 locular (sometimes 1 locule undeveloped). The ‘odd’ carpel (where ascertainable) anterior (?). Styles 1; apical. Stigmas wet type, or dry type (?); papillate, or non-papillate (?); Group II type, Group III type, and Group IV type (?). Placentation axile. Ovules 1–10 per locule (i.e. to ‘several’); ascending; in 1 or 2 rows; arillate; orthotropous to hemianatropous (?).

Fruit and seed features. Fruit non-fleshy; dehiscent; a capsule. Capsules loculicidal. Fruit 4–12 seeded. Seeds copiously endospermic. Endosperm not oily (mealy). Seeds with starch. Cotyledons 1, or 2 (? the second sometimes present, vestigial). Testa operculate (in the form of a characteristic callosity, the ‘embryostega’, covering the embryo). Seedling. Hypocotyl internode present, or absent (?). Seedling collar conspicuous, or not conspicuous (?). Cotyledon hyperphyll elongated, or compact (?). Coleoptile present, or absent (?). First leaf dorsiventral. Primary root ephemeral.

Physiology, biochemistry. Aluminium accumulation not found. Photosynthetic pathway: C₃.

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. Northern Botanical Province.