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DescriptionErect perennial herb with annual, simple or sparsely branched stems, up to 90 cm tall. Milky latex presen. Leaves opposite, linear 1.7-9 cm long, hairy or hairless above, hairless beneath except for appressed pubescence on the midrib. Flowers in 3-7-flowered clusters at the nodes. Calyx hairy. Corolla lobes white, cream, yellow or pale to dark purple, thinly hairy, linear 5.5-9 mm long, usually united at the tips forming a cage, sometimes free and more or less spreading. Corona 1-1.5 mm high, greenish, cream or purplish. Follicles slender, c. 6.5 cm long, finely velvety.