Wahlenbergia Schrad. ex Roth

Annual or perennial herbs with sweet milky juice. Leaves usually alternate, sometimes opposite, sessile or petiolate, margins always with conspicuous, short, blunt, pale, spine-like hydathodes. Young shoots usually sparsely hairy with straight simple hairs 1—2 mm long. Flowers solitary, terminal, regular; corolla glabrous with campanulate tube and (3—)5(—7) spreading lobes, valvate and coherent in bud. Calyx tube glabrous, adnate to the inferior ovary; calyx lobes glabrous, discrete, the same number as the corolla lobes and alternate with them, persistent in fruit. Stamens dehiscent in the elongating bud; anthers oblong, free; filaments delicate, transparent, dilated at the base, arching over the nectary; ovary 2- or 3-celled; style columnar, sometimes thickened and coloured in the upper half which is usually coated with pollen at anthesis. Stigmas are 2-, 3-, or rarely 4-lobed, lobes short, oblong, papillose on the inner surface, opening after the flower has opened. Capsules open by 2 or 3 apical valves within the calyx. Seeds numerous, 0.5—1 mm long, ellipsoid, dark brown and glossy when mature. Flowering Oct—Apr, capsules ripe Nov—Apr in cultivation.

[Reproduced from Petterson (1997, New Zealand J. Bot. 35: 9-54) with permission from The Royal Society of New Zealand.]