Trachypogon spicatus (PROTA)
|Geographic coverage Africa|
|Geographic coverage World|
|Forage / feed|
Trachypogon spicatus (L.f.) Kuntze
- Protologue: Revis. gen. pl. 2: 794 (1891).
- Family: Poaceae (Gramineae)
- Chromosome number: 2n = 20
- Trachypogon plumosus (Humb. & Bonpl. ex Willd.) Nees (1829).
- Giant spear grass, greybeard grass, spiked crinkleawn, arrow grass (En).
Origin and geographic distribution
Trachypogon spicatus is widely distributed in tropical Africa, from Côte d’Ivoire eastward to Ethiopia and southward to South Africa and Madagascar. It also occurs in the Americas, from the southern United States southward to Paraguay.
Trachypogon spicatus is used as thatch on houses. It has some suitability for pulping. It is only grazed when it is very young. It tends to form a dense soil cover providing protection against erosion in areas with high rainfall. It is considered a weed of plantations in Tanzania, but it is easy to control.
Production and international trade
Trachypogon spicatus is only used locally.
The palatability of Trachypogon spicatus is low, except when the foliage is very young. Chemical analysis of fresh material in the early flowering stage in Kenya recorded: crude protein 5.7%, crude fibre 40.2%, ash 9.6%, ether extract 1.8% and nitrogen-free extract 42.7% on a dry matter basis. The root secretes a substance which stimulates germination of the seed of Tagetes minuta L.
Perennial, tufted grass; stems up to 200 cm tall, bearded at the nodes. Leaves alternate; sheath with auricles at the mouth; ligule membranous, without a hairy fringe; blade filiform to linear, 15–40 cm × 1–7 mm, flat or with margins rolled in. Inflorescence terminal, composed of 1(–5) racemes 4–30 cm long; rachis tough, with linear internodes, glabrous. Spikelets paired, 1 subsessile, 1 pedicelled; subsessile spikelet male or sterile, oblong, 8–13 mm long, dorsally compressed, awnless, narrowly and usually inconspicuously winged on the margins above, persistent on the rachis; pedicelled spikelet 2-flowered, subterete, 8–13 mm long including the white bearded callus 1–3 mm long, pungent, obliquely attached to the internode, lower glume oblong, as long as spikelet, obtuse at the apex, leathery, glabrous or hairy, lower floret sterile, reduced to a hyaline lemma, upper floret bisexual, lemma linear, 0.5 mm long, entire, with a flexuous, pubescent or plumose awn 4–10 cm long, palea absent or minute, lodicules 2, stamens 3, ovary glabrous, stigmas 2. Fruit a rounded caryopsis (grain).
In southern Africa Trachypogon spicatus grows mainly during summer and late summer. Its growth rate is moderate to slow. Flowering in southern Africa is in October–May. The awn twists under the influence of moisture which may aid in burying the seed into the soil. Trachypogon spicatus uses the C4 photosynthetic pathway.
Trachypogon is classified in the Andropogoneae. It comprises 3–5 species and is distributed in tropical Africa (including Madagascar) and tropical America. The genus is unusual in that the sessile spikelet is male or sterile and awnless.
Trachypogon spicatus generally occurs in wooded grassland and bushland, sometimes favouring the margins of flood plains and drainage tracts, from sea-level up to 2800 m altitude in equatorial areas and from sea-level up to 1700 m in southern tropical Africa. In South Africa Trachypogon spicatus occurs in the wet, subtropical eastern mountain and Highveld region as well as along the southern to south-western parts at 500–2300 m altitude. Rainfall may be from 600–1500 mm per year. It is a climax species that increases in lightly utilized rangeland. It usually occurs on sandy and gravelly soils, but may also be found near seasonal wetlands. In the Highland Sourveld in South Africa Trachypogon spicatus is characteristic of patches left ungrazed by cattle. In the ungrazed patches, soil moisture and soil depth were higher and the nutrients K and P were lower than in grazed patches, while more palatable grasses dominated in the grazed patches. Regular controlled burning and light grazing increase the proportion of Trachypogon spicatus in the vegetation, as it also increases more palatable species such as Themeda triandra Forssk. In Madagascar it is very common in slightly degraded pasture in Plateau areas. Trachypogon spicatus has shown tolerance of soil copper in spoils of copper mining in Zambia. High levels of copper are accumulated in the roots.
Trachypogon spicatus is not cultivated.
Trachypogon spicatus is widespread and common; it is not in danger of genetic erosion.
Trachypogon spicatus is likely to remain a thatch grass and forage grass of limited value. It may gain importance in erosion control, where its limited palatability is an advantage.
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- L.P.A. Oyen, PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
Correct citation of this article
Oyen, L.P.A., 2011. Trachypogon spicatus (L.f.) Kuntze. [Internet] Record from PROTA4U. Brink, M. & Achigan-Dako, E.G. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. <http://www.prota4u.org/search.asp>.
Accessed 8 March 2020.
- See the Prota4U database.