Scoparia L.

Scientific Description

Common name. Scoparias. Family Scrophulariaceae.

Habit and leaf form. Shrubs, or herbs. Annual; plants with neither basal nor terminal concentrations of leaves. Young stems cylindrical, or tetragonal (or winged). To 0.65 m high. Helophytic, or mesophytic, or xerophytic. Leaves small to medium-sized; opposite, or whorled; 3 per whorl; ‘herbaceous’, or leathery, or membranous; petiolate; simple; epulvinate. Leaf blades dissected, or entire; obovate, or elliptic; if dissected pinnatifid; pinnately veined. Mature leaf blades adaxially glabrous; abaxially glabrous. Leaves without stipules. Leaf blade margins serrate. Leaves without a persistent basal meristem. Leaf anatomy. Hydathodes present (occasionally), or absent. Hairs 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 panicles. The terminal inflorescence unit cymose, or racemose. Inflorescences terminal, or axillary. Flowers pedicellate; bracteate; ebracteolate; minute; regular; 4 merous, or 5 merous; tetracyclic. Free hypanthium absent. Hypogynous disk present. Perianth with distinct calyx and corolla; 8, or 9; 2 -whorled; isomerous, or anisomerous. Calyx present; 4, or 5; 1 -whorled; gamosepalous; lobed. Calyx lobes markedly longer than the tube. Calyx imbricate, or valvate; regular; persistent; when K5, with the median member posterior. Calyx lobes elliptic. Corolla present; 4; 1 -whorled; gamopetalous; lobed; imbricate, or valvate; rotate; regular; glabrous abaxially; hairy adaxially (eglandular tomentose inside mouth); plain; white. Androecium 4. Androecial members adnate (to the corolla); all equal; free of one another; 1 -whorled. Stamens 4. Staminal insertion near the base of the corolla tube. Stamens becoming exserted; isomerous with the perianth; oppositisepalous. Filaments filiform. Anthers all alike; dorsifixed; dehiscing via longitudinal slits; introrse; bilocular (cells confluent, divergent or parallel); tetrasporangiate. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium non-petaloid; syncarpous; eu-syncarpous; superior. Ovary plurilocular; 2 locular. Gynoecium median; stylate. Styles 1; attenuate from the ovary, or from a depression at the top of the ovary; apical; persistent. Stigmas 1; 1–2 - lobed; truncate, or clavate. Placentation axile, or apical. Ovules 50 per locule (to ‘many’); pendulous to ascending; non-arillate; anatropous, or campylotropous, or hemianatropous.

Fruit and seed features. Fruit non-fleshy; not hairy; not spinose; dehiscent; a capsule. Capsules septicidal (the 2 valves cleft at the apex, the septum remaining attached to the valves). Fruit 50 seeded (to ‘many’). Seeds endospermic. Endosperm oily. Seeds minute. Cotyledons 2. Embryo straight to curved.

Special features. Corolla tube straight.

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.