Buttonia

Perennial, slender, trailing or scrambling shrubs, hemiparasitic on roots; stems flexible, much branched, somewhat woody. Leaves opposite, petiolate, +/- ovate in outline, dentate to pinnatifid or pinnatisect, coriaceous. Flowers solitary, axillary, pedicellate, bracteate and bibracteolate. Bracts small, deciduous; bracteoles opposite, subsessile just below calyx, deciduous. Calyx tubular, (4)5-lobed, somewhat leathery, inflated in fruit; tube +/- campanulate or urceolate, 10-veined; lobes ovate, spreading, shorter than tube. Corolla tubular, 5-lobed, slightly irregular; tube narrow at base, inflated and +/- funnel-shaped above, somewhat curved, with wide throat; limb spreading; lobes rounded, shorter than tube, subequal but posterior pair smallest, interior in bud. Stamens 4, didynamous, included, glabrous; upper pair arising in lower part of expanded portion of corolla tube; lower pair arising lower down, in upper part of narrow portion of tube; filaments linear; anthers connivent in pairs, bithecate or unithecate by abortion: upper stamens with one theca empty and vermiform, lower stamens with empty theca absent; staminodes 0. Ovary bilocular, globose, glabrous; ovules many per locule; style filiform, curved above, exserted; stigma obscurely 2-lobed. Fruit a globose, glabrous, loculicidal capsule, enclosed in enlarged, persistent calyx. Seeds many, conical-cylindrical, truncate at both ends; testa reticulate.