General: Biennial herb from a fibrous root; stems erect, branched, fleshy, glabrous and glaucous, 30-100 cm tall.
Leaves: Stem leaves opposite, the pairs arranged at right angles to the adjacent pairs near the stem base, narrowly oblong, 6-12 cm long, 7-15 mm wide, stalkless, broadening in shape upward on the stem; upper leaves distinctly more oval in shape and more or less heart-shaped.
Flowers: Inflorescence of several stalked involucres solitary in the leaf axils; involucres 3 mm long, purplish; glands 4, with short, rounded horns.
Fruits: Capsules, 5-10 mm long, globose, coarsely wrinkled; seeds 4-6 mm long, brownish, net-veined.
If more than one illustration is
available for a species (e.g., separate illustrations were provided for two
subspecies) then links to the separate images will be provided below.
Note that individual subspecies or varietal illustrations are not always available.
