Rhinacantus nasutus (L.) Kurz

Family

Acanthaceae

Synonyms

Rhinacanthus communis Nees.

Vernacular Names

Geographical Distributions

Rhinacantus nasu­tus is probably native to Sri Lanka, India, Indo-­China and southern China, but has been intro­duced long ago in Madagascar, tropical East Africa, Thailand and the Malaysian region (Penin­sular Malaysia, Java, the Moluccas, the Philippines) where it is now widely naturalised and often common.

Description

Rhinacantus nasu­tus is an erect, branched shrub which can grow up to 2(-3) m tall. The stems are obtusely quadrangular and puberulent when young.

The leaves are arranged opposite, simple, ovate to lance-shaped or elliptical, measuring 3-10 cm x 1-5 cm, acute to attenuate at base, with entire margin, acute at apex and puberulent. The petiole is 0.5-2 cm long while stipules are absent.

The inflorescence is axillary and peduncled. The lax cymes are often combined into a leafy and terminal pani­cle and densely appressed pubescent. The flowers are sub­sessile. The sepal is 5-6 mm long and with 5 narrow lobes which are short­ly connate at the base. The petal is 2-lipped, with narrowly cylindrical tube and green. The upper lip is with 2 teeth, measuring 8-10 mm x 2-3 mm and white while the lower lip is with 3 large lobes where the central one measures 10-14 mm x 9-13 mm, and white with red markings at the base. It has 2 stamens that are in­serted near the petal tube apex. The anther cells are in­serted at unequal level. Disk is present. The ovary is supe­rior, 2-locular with 2 ovules in each cell, with 1 style and with a 2-fid stigma.

The fruit is club-shaped, loculicidal, with hairy capsule, measures 17-25 mm long and with sterile basal part.

The seeds are held up on well-developed hooks (retinacula), orbicular, flat and hairy.

Ecology / Cultivation

Rhinacantus nasu­tus is found in thickets, hedges and waste places up to 750 m altitude. It thrives best on moist, well-drained soils, but it is also found in much drier habitats such as rock crevices.

Line Drawing / Photograph

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References

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