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Justicia ladanoides Lam.

Protologue
Tabl. encycl. 1(1): 42 (1791).
Family
Acanthaceae
Chromosome number
2n = 40
Synonyms
Justicia schimperi (Hochst.) Dandy (1956), Justicia insularis auct. non T.Anders.
Vernacular names
Justicia, tettu (En, Fr).
Origin and geographic distribution
Justicia ladanoides occurs wild from Senegal and Gambia east to Eritrea, Ethiopia and Somalia, but not further south than DR Congo, Kenya and Uganda. It is cultivated in home gardens in West and Central Africa, especially in Guinea, Sierra Leone, Ghana, Togo, Benin, Nigeria, Cameroon and DR Congo.
Uses
In tropical Africa, the tender and slightly slimy leaves and shoots of Justicia ladanoides are an appreciated leafy vegetable; they are also cooked into soup or stew. Leaves of sweet potato are sometimes added to prepare soup, and in western Cameroon Justicia ladanoides leaves are added to groundnut soup. Occasionally, Justicia ladanoides is also used as forage and planted as an ornamental. The leaves are used for the treatment of wounds and, mixed with oil and salt, they are eaten to treat cardiac disorder. In Ghana and Togo, a leaf decoction is given to children for the treatment of indigestion.
Production and international trade
Justicia ladanoides is a low value vegetable, marketed in village markets and occasionally in urban markets. There is no international trade and there are no production data.
Properties
The composition of fresh Justicia leaves per 100 g edible portion is: water 86.8 g, energy 138 kJ (33 kcal), protein 3.3 g, fat 0.4 g, carbohydrate 6.2 g, fibre 1.7 g, Ca 510 mg, P 70 mg (Leung, W.-T.W., Busson, F. & Jardin, C., 1968).
Description
Annual or perennial herb up to 2 m tall; stem angular, glabrous to pubescent, basal part often swollen and with aerial roots. Leaves decussately opposite, simple, almost glabrous to densely pubescent; petiole up to 6 cm long; blade linear or narrowly lanceolate to ovate, obovate or elliptical, 1–11 cm × 0.5–5 cm, base attenuate to truncate, apex obtuse to acuminate, margin entire to crenate. Inflorescence an axillary or terminal congested spike, few-flowered, with narrow bracts. Flowers bisexual, sessile, zygomorphic, 5-merous, usually crimson, sometimes white; calyx up to 1 cm long, with short tube and longer lobes; corolla tubular, up to 2.5 cm long, 2-lipped, lower lip longest and widest and 3-lobed, upper lip narrower and 2-lobed; stamens 2, hidden in upper lip of corolla; ovary superior, 2-celled, style long and slender, stigma with 2 unequal lobes. Fruit an ovoid to ellipsoid capsule c. 10 mm × 3 mm, yellow-brown to white, explosively dehiscent, 4-seeded. Seeds c. 2 mm long, tuberculate. Seedling with epigeal germination.
Other botanical information
Justicia ladanoides belongs to section Harnieria. It has been confused with species of the so-called Justicia striata complex. Some species of this complex are also used as a vegetable in a similar way to Justicia ladanoides. An example is Justicia heterocarpa T.Anders.; in Tanzania, its leaves are cooked alone or with other vegetables and served with pounded groundnuts or coconut milk. The Justicia striata complex comprises many taxa, which are clearly different in some regions, but in other regions the differences become more vague because of intermediates. This has resulted in conflicting taxonomic treatments varying from the acceptance of only a single variable species within the complex to the distinction of 10 species. Justicia ladanoides differs from the Justicia striata complex in its pollination system.
Growth and development
The vegetative growth of Justicia ladanoides is slow; it takes several weeks after sowing to cover the soil. Flowering occurs at the end of the rainy season and the beginning of the dry season. The production of shoots is concentrated at the base of the plant 10–15 cm above the soil surface and shoot production continues after flowering. In Justicia ladanoides the stigma is receptive at the same time as the anthers are mature. The style exceeds the anthers, and one of the stigma lobes gradually bends down, coming very close to the anthers after some days, thereby gradually increasing the chance of self-pollination. The flowers of the Justicia striata complex are protandrous. When the female phase begins, the stamens bend away from the upper lip thereby exposing the style. Pollination is effected by insects.
Ecology
Justicia ladanoides occurs in a wide range of habitats, from sea-level up to 2600 m altitude, and from moist rainforest to dry savanna regions. It is also found in waste and cultivated land, refuse heaps, grassland and forest edges. It can be found on sandy and loamy soils, but requires rich humus soil and slight shade for optimum growth. It thrives with annual rainfall ranging from 1000–2000 mm, day temperatures of 25–35°C and night temperatures of 20–27°C; it does not tolerate low temperatures.
Management
Weeding is needed 2–3 times per growth cycle. Organic manure and fertilizer (e.g. NPK 10–10–20) are beneficial for good vegetative growth. Irrigation 1–2 times per week is desirable during the dry season.
Propagation and planting
Justicia ladanoides can be propagated by seed and by cuttings. The seed remains dormant during the dry season and germinates readily with the onset of rains. The number of seeds/g is about 480. Seed production is difficult because the seeds are scattered when the fruits split open. The fruits can be gathered immediately when the colour changes from green to white, or whole branches with infructescences are harvested and dried. The seed may be drilled in rows spaced at 40–50 cm. Young seedlings are thinned, allowing 30–40 cm between plants in the rows. In cultivation it is easiest to take rooted cuttings obtained from the basal parts of the stem. Spontaneous seedlings can be uprooted and transplanted on vegetable beds. Stem cuttings about 15 cm long can also be planted 30–40 cm apart. Planting on well-prepared, raised vegetable beds is required for good vegetative growth.
Diseases and pests
As a weedy and seldomly cultivated plant, the disease and pest problems in Justicia ladanoides are not prominent. Light attack of flea beetles may occur but the plant is reported to be tolerant to Zonocerus variegatus attack. Colletotrichum fungi may attack full-grown plants causing dark coloration, shrivelling and wilting of the root collar.
Harvesting
Young plants of Justicia ladanoides can be harvested by uprooting when 3–5 weeks old, but the main harvest is by cutting. The first cutting is at a height 5–6 cm above the ground when the plant height is 20–25 cm, or 6–7 weeks after planting from seed or cutting. Repeated cuttings promote rapid production of shoots. Harvesting can be carried out at 10-day intervals, preferably in the morning or late afternoon to maintain a fresh and attractive vegetable for marketing.
Yield
A yield of fresh Justicia ladanoides leaves of up to 20 kg per 10 m2 bed may be obtained from repeated harvests over a 4-month period.
Handling after harvest
The leaves and tender shoots are tied into bundles of 0.3–0.4 kg each. Roots of uprooted young seedlings are washed before these are packed for the market. Water is sprinkled at regular intervals on the vegetable to maintain a fresh appearance for marketing.
Genetic resources
There is wide variation within Justicia ladanoides, even within local types. Improved cultivars are not available and there are no germplasm collections. There is no immediate threat of genetic erosion of the existing variation. Collection and maintenance of the germplasm is required for genetic studies and selection of improved cultivars.
Prospects
Justicia ladanoides has no immediate potential of high commercial value like amaranth, celosia and jew’s mallow. As a shade-tolerant plant, it has good potential for production under the low light intensity conditions of African home and backyard gardens. The ability of the plant to produce leaves from the rainy season until well into the dry season makes it a good source of a regular supply of vegetables for the family. Its potential use as a dry season vegetable should also be investigated.
Major references
• Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families A–D. Royal Botanic Gardens, Kew, United Kingdom. 960 pp.
• Hedrén, M., 1989. Justicia sect. Harnieria (Acanthaceae) in tropical Africa. Acta Universitatis Upsaliensis. Symbolae Botanicae Upsaliensis 29(1): 1–141.
• Morton, J.K., 1978. A revision of the Justicia insularis-striata complex (Acanthaceae). Kew Bulletin 32(2): 433–448.
• van Epenhuijsen, C.W., 1974. Growing native vegetables in Nigeria. FAO, Rome, Italy. 113 pp.
Other references
• Gbile, Z.O., 1984. Vernacular names of Nigerian plants (Yoruba). Forestry Research Institute of Nigeria. 101 pp.
• Hedrén, M., 1990. The Justicia striata complex in tropical Africa (Justicia sect. Harnieria, Acanthaceae). Nordic Journal of Botany 10: 357–398.
• Leung, W.-T.W., Busson, F. & Jardin, C., 1968. Food composition table for use in Africa. FAO, Rome, Italy. 306 pp.
• Martin, F.W. & Ruberté, R.M., 1975. Edible leaves of the tropics. Agency for International Development Department of State, and the Agricultural Research Service, U.S. Department of Agriculture, United States. 235 pp.
• Rehm, S. & Espig, G., 1991. The cultivated plants of the tropics and subtropics: cultivation, economic value, utilization. CTA, Ede, Netherlands. 552 pp.
• Ruffo, C.K., Birnie, A. & Tengnäs, B., 2002. Edible wild plants of Tanzania. Technical Handbook No 27. Regional Land Management Unit/ SIDA, Nairobi, Kenya. 766 pp.
• Stevels, J.M.C., 1990. Légumes traditionnels du Cameroun: une étude agrobotanique. Wageningen Agricultural University Papers No 90-1. Wageningen University, Wageningen, Netherlands. 262 pp.
• Terra, G.J.A., 1973. Tropical vegetables. Communication 54. Royal Tropical Institute, Amsterdam, Netherlands. 107 pp.
• van der Zon, A.P.M. & Grubben, G.J.H., 1976. Les légumes-feuilles spontanés et cultivés du Sud-Dahomey. Communication 65. Département des Recherches Agronomiques, Koninklijk Instituut voor de Tropen, Amsterdam, Netherlands. 111 pp.
Sources of illustration
• Hedrén, M., 1989. Justicia sect. Harnieria (Acanthaceae) in tropical Africa. Acta Universitatis Upsaliensis. Symbolae Botanicae Upsaliensis 29(1): 1–141.
• van Epenhuijsen, C.W., 1974. Growing native vegetables in Nigeria. FAO, Rome, Italy. 113 pp.
Author(s)
O.A. Denton
National Horticultural Research Institute, P.M.B. 5432, Idi-Ishin, Ibadan, Nigeria


Editors
G.J.H. Grubben
Prins Hendriklaan 24, 1401 AT Bussum, Netherlands
O.A. Denton
National Horticultural Research Institute, P.M.B. 5432, Idi-Ishin, Ibadan, Nigeria
Associate Editors
C.-M. Messiaen
Bat. B 3, Résidence La Guirlande, 75, rue de Fontcarrade, 34070 Montpellier, France
R.R. Schippers
De Boeier 7, 3742 GD Baarn, Netherlands
General editors
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
L.P.A. Oyen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
Illustrator
Achmad Satiri Nurhaman
PROSEA Network Office, P.O. Box 332, Bogor 16122, Indonesia

Correct citation of this article:
Denton, O.A., 2004. Justicia ladanoides Lam. In: Grubben, G.J.H. & Denton, O.A. (Editors). PROTA 2: Vegetables/Légumes. [CD-Rom]. PROTA, Wageningen, Netherlands.
Distribution Map wild and planted


1, part of young plant; 2, flowering branch; 3, fruit.
Redrawn and adapted by Achmad Satiri Nurhaman