Dischisma Choisy

Scientific Description

Common name. Dischismas. Family Scrophulariaceae.

Habit and leaf form. Shrubs, or herbs. Annual, or perennial; plants with neither basal nor terminal concentrations of leaves; to 0.2 m high. Helophytic, or mesophytic, or xerophytic. Leaves small to medium-sized; alternate, or alternate and opposite (then lowermost opposite); when alternate spiral, or four-ranked; ‘herbaceous’, or leathery, or membranous; sessile; simple; epulvinate. Leaf blades entire; linear, or obovate, or oblong; pinnately veined. Mature leaf blades adaxially glabrous, or pubescent; abaxially glabrous, or pubescent. Leaves without stipules. Leaf blade margins entire, or dentate. Leaves without a persistent basal meristem. Leaf anatomy. Hydathodes present (occasionally), or absent. Hairs present, or absent; glandular hairs absent. Stem anatomy. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in spikes. The terminal inflorescence unit cymose, or racemose. Inflorescences terminal; often dense. Flowers bracteate (the bracts hiding the flowers); ebracteolate; minute to small; very irregular; zygomorphic; 2 merous, or 4 merous; tetracyclic. Free hypanthium absent. Hypogynous disk present. Perianth with distinct calyx and corolla; 6; 2 -whorled; anisomerous. Calyx present; 2; 1 -whorled; polysepalous; imbricate, or valvate; persistent. Sepals linear, or ovate to oblong. Corolla present; 4; 1 -whorled; gamopetalous; lobed. Corolla lobes markedly shorter than the tube. Corolla tube not noticeably adaxially split (but deeply abaxially split). Corolla imbricate, or valvate; unequal but not bilabiate (lobes unequal), or bilabiate (i.e. interpretable as having the lower lip suppressed); plain; white. Androecium 4. Androecial members adnate (to the corolla); markedly unequal; free of one another; 1 -whorled. Stamens 4; all inserted at the same level (below corolla lobes), or inserted at markedly different levels (when one pair sometimes deeper in the tube); becoming exserted, or remaining included; didynamous; isomerous with the perianth; oppositisepalous. Anthers dehiscing via longitudinal slits; introrse; bilocular (according to Marchant et al (1987)); tetrasporangiate. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium non-petaloid; syncarpous; eu-syncarpous; superior. Ovary plurilocular; 2 locular. Gynoecium median; stylate. Styles 1; simple; attenuate from the ovary, or from a depression at the top of the ovary; apical; becoming exserted, or not becoming exserted. Stigmas 1; 1 - lobed. Placentation apical. Ovules 1 per locule; pendulous; non-arillate; anatropous, or campylotropous, or hemianatropous.

Fruit and seed features. Fruit non-fleshy; not hairy; not spinose; indehiscent, or a schizocarp. Mericarps when schizocarpic, 2. Fruit 2 seeded, or 1 seeded (in each mericarp). Seeds endospermic. Endosperm oily. Seeds minute to small; winged, or wingless (? - often angled). Cotyledons 2. Embryo straight to curved.

Special features. Corolla tube exceeding the calyx, or not exceeding the calyx; straight. The upper lip of the corolla incorporating all the members, the lower suppressed; (posterior, adaxial) lip of the corolla 4 lobed. Lower (abaxial) lip of the corolla suppressed.

Geography, cytology, number of species. Adventive. Australian states and territories: Western Australia and South Australia. South-West Botanical Province.

Etymology. From the Greek for "double" and "foot"; refers to the separate caudicles of the two pollen masses.