Ruellia tuberosa L.

Ruellia tuberosa L.



Vernacular Names

Thailand Toi ting (Bangkok).
Vietnam Q[ur]a n[oor], tanh t[as]ch.

Geographical Distributions

Ruellia tuberosa originates from tropical America, but is naturalized in Southeast Asia (Thailand, Peninsular Malaysia, Java) and elsewhere in the tropics (India, Sri Lanka, Africa), as an escape from cultivation and as an ornament.


R. tuberosa is an erect, perennial herb, which can grow up to 90 cm tall. It is with elongately tuberous roots and slightly four-edged stem that thickens above the nodes.

The leaves are arranged opposite, simple and entire, oblong to oblong-obovate, measuring 6-18 cm x 3-9 cm, decurrent at base, obtuse to rounded at apex, sparingly hairy or hairless and with cystoliths. The petiole is up to 1.5 cm long and connected by transverse ridges. Stipules are absent.

The inflorescence is an axillary cyme, rather lax and 1- to 15-flowered. The bracts are narrow and up to 9 mm long. The peduncle is up to 2.5 cm long. The flowers are bisexual and 5-merous. The pedicel is up to 2.5 cm long. The sepal is 2-3 cm long and partite with narrow and finally reflexed segments. The petal is 5-6 cm long, infundibular with narrow base, unequally to slightly equally lobed, with rounded lobes which are up to 2.5 cm long, irregularly sinuate-dentate and bright violet to pale blue but sometimes white. There are 4 stamens inserted at base of petal tube and didynamous. The ovary is superior and 2-celled while the style is awl-shaped with 2 unequal stigmatic lobes.

The fruit 2-3 cm long is a spindle-shaped capsule and many-seeded.

The seeds are orbicular, compressed and ringed with hygroscopic hairs.

Line Drawing / Photograph



  1. Plant Resources of South-East Asia No.12(3): Medicinal and poisonous plants 2.