Rough Buttonweed
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Rough Buttonweed
A Naturalized Photo: Preetha P.S.
Common name: Rough Buttonweed
Botanical name: Hexasepalum tere    Family: Rubiaceae (Coffee family)
Synonyms: Diodia teres, Diodella teres, Spermacoce diodina

Rough Buttonweed is an annual herbs, stems erect or decumbent, branched, up to 45 cm high, scabrous with hairy, woody. Leaves stalkless or nearly stalkless, blade linear, tip pointed, base almost heart-shaped, margins rough-fringed with hairs, tips with a prominent setae, 13-25 x 3-7 mm, scabrous; stipules, fused with leaf-stalk, bristly at tip; fimbriae 9-11, 4-6 mm long. Flowers are borne in leaf-axils, in 1-4 flowered clusters. Flowers are about 5.5 x 3 mm, stalkless. Sepal-cup 4-lobed, hairless to scabrous outside, persistent; sepals unequal, ovate-lanceshaped, 0.6-1.5 x 0.3-0.6 mm, rough at margins, pointed, bristly at tip. Flowers are funnel-shaped, about 4.2 mm long, scabrous, pale purple; tube 3-3.4 mm long, limb 4-lobed; petals ovate, about 1.8 x 1.2 mm, fringed with hairs, pointed at tip, rough. Stamens are 4, protruding. Style is 3-3.5 mm long. Capsules are obovoid to obconical, 2.2-3 x 1.7-2 mm, sparsely bristly above, crowned by persistent sepal-cup. Rough Buttonweed is native of tropical American regions, and is believed to be an invasive weed in India. Flowering: July-December.

Identification credit: Preetha P.S. Photographed in Kollam, Kerala.

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