Rungia laxiflora (PROSEA)
Introduction |
Rungia laxiflora C.B. Clarke
- Protologue: Journ. As. Soc. Beng., Pt. 2, Nat. Hist. 74: 698 (1908).
- Family: Acanthaceae
- Chromosome number: 2n= unknown
Synonyms
Justicia uber C.B. Clarke (1908), Justicia bracteata Ridley (1909), Justicia clarkeana Ridley (1923).
Vernacular names
- Malaysia: puding hutan jantan, serupet, akar ratus (Peninsular).
Origin and geographic distribution
R. laxiflora occurs in southern peninsular Thailand and Peninsular Malaysia.
Uses
In Peninsular Malaysia, the leaves have been used externally as a poultice to treat headache and abdominal complaints, whereas the plant has been used internally as an ingredient in a complex decoction to treat diarrhoea.
R. klossii S. Moore is a popular vegetable in the highlands of New Guinea. The leaves are also used in a poison antidote, in mixtures with other plants which induce vomiting. Roasted or boiled leaves are eaten to treat colds, influenza and sore throat.
The leaves of the African R. grandis T. Anderson are used in Gabon as anthelmintic and the bark as an antidysenteric.
Properties
There is no information on phytochemistry and pharmacological properties of R. laxiflora . A fair quantity of alkaloids has been detected in R. grandis material from Nigeria, e.g. macrorin and isomacrorin.
Botany
A herb up to 90(-150) cm tall, sometimes straggling, glabrous or slightly hairy. Leaves opposite, ovate-elliptical to elliptical-lanceolate, 5-25 cm × 2.5-10 cm, narrowed at both ends, with cystoliths; petiole 0.5-3 cm long; stipules absent. Inflorescence an axillary or terminal spike with flowers arranged on one side, up to 15 cm long, distinctly bracteate. Flowers bisexual; calyx deeply 5-fid; corolla 6-15 mm long, tube short, widened upwards, 2-lipped, upper lip slightly emarginate, lower lip shortly 3-lobed, creamy-yellow or whitish, often striped or spotted purplish on lips; stamens 2, inserted at the base of the widening of the corolla tube, anthers 2-celled with lower cell basally spurred; ovary superior, 2-celled, style entire or shortly 2-lobed. Fruit a clavate capsule 8-15 mm long, with rising elastic placenta, 4-seeded. Seeds compressed orbicular, pubescent, pustulate.
Rungia comprises approximately 50 species and occurs in tropical Africa and tropical Asia. It is related to Justicia , but can be distinguished by the combination of the following characters: placentas in the fruit rising, and inflorescence always spicate with one bract sterile and the other fertile at each node. R. laxiflora is a variable species, particularly in the shape and size of the bracts and bracteoles, and many species have been distinguished in the past. However, the variation seems to be continuous and does not support specific distinction.
Ecology
R. laxiflora is locally common in lowland and lower montane forest in Peninsular Malaysia, up to 1300 m altitude. It is also found on limestone.
Genetic resources
The area of distribution of R. laxiflora seems limited; up till now it has only been recorded from Peninsular Malaysia and the adjacent part of peninsular Thailand. However, in these areas it is common, at least locally, and seems not to be endangered.
Prospects
The topical applications of R. laxiflora are comparable to those of other Acanthaceae , e.g. Hygrophila ringens (L.) R.Br. ex Steudel, Justicia and Peristrophe species, and Ptyssiglottis kunthiana (Nees) B. Hansen. Research on active compounds and pharmacological properties for these species is desirable. A taxonomic treatment of the genus Rungia is urgently needed to gain an insight into the delimitation and distribution of its species.
Literature
121, 363.
Other selected sources
120, 331, 347, 789, 853.
Main genus page
Authors
R.H.M.J. Lemmens