sect. Monanthema N. Robson

Perennial herbs up to 0.4 m tall, with stems erect to prostrate, creeping and branching at base, glabrous, with dark (black or rarely red) glands on leaves, seals, petals and anthers; branching lateral, from various nodes.  Stems (mature) terete or (when slender) 2-4(6)-lined, eglandular or (4. H. himalaicum but very rarely) with few reddish glands on lines.  Leaves opposite, decussate, sessile or to 3 mm pseudopetiolate, free, persistent; lamina entire or occasionally dark-glandular-ciliate, without or occasionally with gland-fringed auricles, with venation pinnate, closed and tertiary reticulation dense or very rarely rather dense to lax; laminar glands pale and/or black, punctiform to striiform, dense to almost absent, relatively small; ventral resin glands absent.  Inflorescence 1-15(-c. 50)-flowered, with branching dichasial to monochasial from 1-2 nodes, sometimes with subsidiary branches from up to 4 nodes below; bracts and bracteoles gland-fringed and glandular-auriculate or entire and then usually foliar.  Flowers stellate, homostylous.  Sepals 5(4), free, persistent, erect in fruit, with margin glandular-ciliate to entire; veins 5-7(9), laminar glands pale and/or dark, linear to punctiform; marginal or submarginal glands black or reddish.  Petals 5(4), persistent, deflexed to spreading, crumpling after flowering, with or without apiculus, margin entire or with apical glandular cilium; laminar glands pale and/or dark, linear to punctiform, and usually 1-4 sessile or subapical (immersed) dark glands.  Stamen fascicles 5, united 2+2+1 (i.e. '3') or rarely 2+1+1+1 (i.e. '4') , persistent, with stamens totalling 10-45, filaments basally united; anther gland dark (black or rarely reddish); pollen type X.  Ovary with (2)3(4) completely axile (or rarely incompletely axile to parietal) placentae, each ¥-ovulate; styles (2)3(4), free, divergent from discrete bases; stigmas narrow.  Capsule (2)3(4)-valved, chartaceous to papyraceous, with valves longitudinally vittate.  Seeds cylindric, not carinate or appendiculate; testa scalariform-reticulate to scalariform or foveolate.