Herbs, perennial, weak to climbing or trailing, usually much branched. Stems 20-70 cm, 4-angled to 4-winged, villosulous to hirtellous and/or sparsely aculeolate to smooth. Leaves on main stems in whorls of up to 6(-8), sessile or with very short (ca. 1 mm) petiole; blade drying papery to leathery, adaxially dark green and shiny, abaxially paler, oblanceolate-oblong, oblanceolate, or obovate, (5-)10-20(-25) × (1-)1.5-4(-6) mm, adaxially scaberulous, hirtellous to glabrous, abaxially densely villosulous, hirsute, pilose to glabrous, base acute to cuneate, margins retrorsely aculeolate and ± hairy, flat to thinly revolute, apex obtuse, rounded, truncate, or emarginate and shortly mucronate; vein 1. Inflorescences ± paniculate, up to 18 cm, expanding through growing season, with terminal and axillary, several-to many-flowered cymes; peduncles glabrous to rarely villosulous, regularly spreading to divaricate, with a dichasial branching pattern, at most nodes with leaflike bracts (1-4 mm); pedicels 0.2-2.5 mm. Ovary obovoid, 0.2-0.3 mm, mostly glabrous or smooth, but sometimes also verrucose, hirtellous, or with undeveloped uncinate trichomes. Corolla greenish white or yellow, rotate, 1.5-2 mm in diam., glabrous, lobed for 2/3 or more; lobes 4, triangular-ovate, filamentous-aristate (rarely only acute). Mericarps ellipsoid, 1-2 mm, glabrous and smooth or rarely granular-tuberculate, hirtellous, or with appressed to spreading hooked trichomes, on pedicels often slightly elongating to 4 mm. Fl. and fr. (May-)Jun-Sep(-Oct).
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