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Centranthera R.Br.

Reference
Prodr.Fl.Nov.Holland. 438 (1810)
Name Status
Current

Scientific Description

Family Scrophulariaceae.

Habit and leaf form. Herbs. ‘Normal’ plants, or plants of very peculiar form (parasitic). Partially parasitic. On roots of the host. Annual; plants with a basal concentration of leaves, or with neither basal nor terminal concentrations of leaves; to 0.55 m high. Helophytic, or mesophytic, or xerophytic. Leaves small to medium-sized; opposite, or alternate and opposite (alternate above); when alternate spiral, or four-ranked; ‘herbaceous’, or leathery, or membranous; sessile; sheathing, or non-sheathing; simple; epulvinate. Leaf blades entire; linear, or ovate; pinnately veined. Mature leaf blades adaxially scabrous, or pubescent; abaxially scabrous, 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; 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 racemes. The terminal inflorescence unit cymose, or racemose. Inflorescences terminal, or axillary; spike-like. Flowers pedicellate to sessile; bracteate; bracteolate; small to medium-sized; somewhat irregular, or very irregular; zygomorphic; tetracyclic. Free hypanthium absent. Hypogynous disk present. Perianth with distinct calyx and corolla; 7–10; 2 -whorled; isomerous, or anisomerous. Calyx present; 2–5 (sometimes entire); 1 -whorled; gamosepalous (and split down abaxial side); 2–5 lobed, or entire; toothed. Calyx lobes markedly shorter than the tube. Calyx erect; imbricate, or valvate. Degree of gamosepaly, maximum length joined/total calyx length 1. Calyx unequal but not bilabiate, or bilabiate, or regular; persistent; accrescent, or non-accrescent; when K5, with the median member posterior. Corolla present; 5; 1 -whorled; gamopetalous. Corolla lobes markedly shorter than the tube. Corolla imbricate, or valvate; tube dilated from point of exsertion from calyx; regular, or bilabiate; glabrous abaxially; glabrous adaxially; plain, or with contrasting markings; white, or pink, or purple. Androecium 4. Androecial members adnate (to the corolla); markedly unequal; coherent; 1 -whorled. Stamens 4. Staminal insertion near the base of the corolla tube. Stamens remaining included; didynamous; reduced in number relative to the adjacent perianth; oppositisepalous. Filaments hairy. Anthers cohering (in pairs); dehiscing via longitudinal slits; introrse; bilocular (cells confluent, distally awned, 1 cell sometimes smaller than the other and then sometimes empty); tetrasporangiate. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium non-petaloid; syncarpous; synstylovarious to 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. Stigmas 1; 1–2 - lobed. 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; dehiscent; a capsule. Capsules loculicidal (with the septum remaining attached to the 2 valves). Fruit 50 seeded (to ‘many’). Seeds endospermic. Endosperm oily. Seeds minute; wingless (and twisted). Cotyledons 2. Embryo straight to curved.

Special features. Corolla tube exceeding the calyx; straight, or curved. The upper lip of the corolla incorporating 2 members, the lower 3; (posterior, adaxial) lip of the corolla bilobed. Lower (abaxial) lip of the corolla 3 lobed.

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

Etymology. From the Greek for "point, spike" and "anther"; the anthers have awn-like points.

H.R. Coleman, 8 September 2016

Taxonomic Literature

  • Wheeler, J. R.; Rye, B. L.; Koch, B. L.; Wilson, A. J. G.; Western Australian Herbarium 1992. Flora of the Kimberley region. Western Australian Herbarium.. Como, W.A..