Barleria macrostegia Nees
Common names: tongklapper (Afr.)
A groundcover with a strange flower cluster.
Barleria macrostegia is a trailing perennial herb, with much-branched, prostrate stems, growing up to 500 mm long. The branches are hairy and develop out of a woody rootstock. The leaves are opposite, oblong or elliptic and the leaf margins are wavy with long white hairs, the leaves tapering at the base and the apex (leaf tip), ending in a sharp point.
The mauve flowers are borne in a 2–4, unilateral (one-sided) flower cluster, 20–75 mm long. The corolla is 2-lipped, the upper lip 4-lobed, and lower lip 1-lobed. The petals are the same size and evenly spaced. The outer calyx lobes are ovate and covered with prominent long hairs. The posticous (the side towards the axil) calyx lobe margins are entire and the apex tapering into a sharp spine. The anticous (the side away from the axil) calyx lobe margins are entire, but the apex does not end in a prominent spine. The bracteoles are imbricated (with margins of structures overlapping like shingles on a roof), enclosing the calyx, they are ovate and the margins entire, both the margins and veins are covered with long white hairs. The apex tapered into a sharp spine.
The seed capsules are elliptic, with 4 seeds per capsule. The ripe fruit capsules, turn brown when mature, opening explosively, shooting out the seeds, when moistened. It flowers in summer and autumn, from December to June.
According to the Red list of South African plants Barleria macrostegia is assessed as Least Concern (LC).
Distribution and habitat
Barleria macrostegia is found growing in South Africa, Zimbabwe, Botswana and Namibia, and in South Africa it occurs in the Provinces of Limpopo, Gauteng, North West, Free State and Northern Cape. It grows in grassland, wooded grassland, roadsides and fallow land, often in loamy or sandy soils.
Derivation of name and historical aspects
The genus Barleria consists of a large group of about 300 species of shrubs, shrublets and herbs distributed worldwide. The genus is named after the Dominican monk and French botanist, Jacques Barrelier (1606–1673). The species name macrostegia means ‘large roof’ from macro, meaning ‘large’, and stegia, meaning ‘roof’ or ‘covering’, referring to the bracteoles that enclose the flower cluster. The common name tongklapper, meaning ‘tongue cracker’, comes from the practice of placing a ripe seed capsule under your tongue and waiting for it to pop open, like a cracker.
Barleria macrostegia is pollinated by insects and attracts various species of butterflies.
No known uses. This species is frost resistant, grows well in poor soils, does not need a lot of water and prefers to grow in full sun. It is an excellent, water-wise, low-maintenance, summer flowering plant for grassland gardens.
Growing Barleria macrostegia
Barleria macrostegia grows only from seed. Harvest the seed from the ripe, brown capsules. Sow the seed in summer, from October to February, in a container in a mix of 1 part washed river sand and 2 parts potting medium. Place the container in a shady spot and water once a week. Germination starts to take place in 14 days. Transplant the seedlings when they are 10 cm tall.
Barleria macrostegia does well in hot, sunny spots in your garden, for example in your succulent garden. There are no specific pests or diseases affecting Barleria macrostegia.
- Flora capensis entry for Barleria macrostegia, accessed via JSTOR Global Plants: https://plants.jstor.org/compilation/BARLERIA.macrostegia.
- Little, J. R. & Jones, C.E. 1980. A dictionary of botany. Van Nostrand Reinhold Compony, New York, Cincinnatti, Toronto, Melbourne.
- Nyirenda, F,C. 2012. Morphological variation in five related species of Barleria (Acanthaceae). Dissertation for Masters of Science, University of the Witwatersrand.
- Victor, J.E. 2004. Barleria macrostegia Nees. National Assessment: Red List of South African Plants version 2017.1. Accessed on 2019/07/15
- iNaturalist. Observations of Barleria macrostegia. https://www.inaturalist.org/taxa/580982-Barleria-macrostegia/browse_photos
Lowveld National Botanical Garden
Plant Type: Ground Cover, Shrub
SA Distribution: Free State, Gauteng, Limpopo, Mpumalanga, North West
Soil type: Sandy, Loam
Flowering season: Early Summer, Late Summer, Autumn
Flower colour: Mauve/Lilac
Aspect: Full Sun
Gardening skill: Challenging