Rhytachne rottboellioides (PROTA)

Plant Resources of Tropical Africa Introduction

List of species

General importance
Geographic coverage Africa
Geographic coverage World
Forage / feed
Fibre

Rhytachne rottboellioides Desv.

Protologue: Ham., Prodr. Pl. Ind. Occ.: 12 (1825).

Family: Poaceae (Gramineae)

Chromosome number: n = 16

Synonyms

• Rhytachne mannii Stapf (1894),
• Rhytachne benguellensis Rendle (1899).

Origin and geographic distribution

Rhytachne rottboellioides occurs widely in most countries of tropical Africa, including Madagascar, and in eastern Latin America, from Cuba to Argentina.

Uses

In northern Sierra Leone and in Guinea people make fancy baskets from the stems. Konkomba people in Togo use the stems for making fine, light straw hats. Young growth is grazed by cattle, but is of moderate quality only.

Production and international trade

Rhytachne rottboellioides is only used and traded locally.

Botany

Perennial, densely tufted, slender to robust grass; stems up to 100 cm tall. Leaves alternate; lower parts of lower sheaths persistent; ligule a short membrane; blade narrow, 5–25 cm × 0.5–1 mm, bristly hairy, margins rolled inward. Inflorescence a single, terminal, cylindrical raceme 2–20(–25) cm long; rachis fragile at the nodes; internodes club-shaped, as long as the sessile spikelets, glabrous. Spikelets in pairs, 1 sessile and 1 pedicelled; sessile spikelet fertile, 2-flowererd, narrowly ovate to oblong, 2–5(–6) mm long, convex on the back, callus truncate, with prominent central peg, lower glume oblong, sharply inflexed in the lower half, crustaceous, variously rough with wrinkles or short points, rarely almost smooth, 5–9-veined, apex obtuse, acuminate or with 2 small points, with or without an up to 5 mm long awn, upper glume awnless or with awn up to 5 mm long, basal floret male, lemma lanceolate, nearly as long as spikelet, hyaline, 3-veined, acute, palea present, upper floret bisexual, lemma oblong, hyaline, without keel, 1–3-veined, apex acute, margin ciliolate, palea absent or minute, lodicules 2, stamens 3, ovary 1-locular, stigmas 2; pedicelled spikelet sterile, suppressed or almost so, represented by a curved pedicel as long as the sessile spikelet, sometimes with awn up to 5 mm long. Fruit an oblong caryopsis (grain), dorsally compressed.

Rhytachne rottboellioides shows extreme variation in habit, size, spikelet size and corrugation of the lower glume, and in the presence or absence of awns. In Benin it flowers in May–October.

Rhytachne is classified in the Andropogoneae. It comprises about 12 species and is distributed in the tropics of the Americas and Africa (including Madagascar), with 1 species in China. The genus is badly in need of revision.

Rhytachne subgibbosa (Winkl. ex Hack.) Clayton is widespread in South America. Remarkably, it also occurs by Lake Bangweulu in northern Zambia. While the Zambian specimens are extreme in almost all features for Rhytachne subgibbosa, it is too similar to separate it as a distinct species. It has been hypothesized that Rhytachne subgibbosa is not distinct from Rhytachne rottboellioides, but an incidental cluster of character states in the large gene pool that constitutes the very variable Rhytachne rottboellioides on both continents. The annual forms of Rhytachne rottboellioides in Latin America have been classified in a separate species: Rhytachne gonzalezii Davidse.

Ecology

Rhytachne rottboellioides grows in swamps and seasonally wet grassland, sometimes on shallow soils over iron-pans, from sea-level up to 2250 m altitude near the equator and up to 1500 m altitude near the tropic of cancer. It is able to quickly invade humid fallow land. In Malawi Rhytachne rottboellioides is a weed of irrigated rice fields.

Management

Rhytachne rottboellioides only grows wild.

Genetic resources

As Rhytachne rottboellioides is extremely widely distributed and sometimes weedy, its great genetic variability does not seem to be in danger of genetic erosion.

Prospects

Rhytachne rottboellioides is likely to remain a fodder grass of moderate quality and of local interest only as a source of material for wickerwork.

Major references

• Burkill, H.M., 1994. The useful plants of West Tropical Africa. 2nd Edition. Volume 2, Families E–I. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 636 pp.

• Clayton, W.D. & Renvoize, S.A., 1982. Gramineae (part 3). In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. pp. 451–898.

• Clayton, W.D., Vorontsova, M.S., Harman, K.T. & Williamson, H., 2002–. GrassBase - the online world grass flora. [Internet] Royal Botanic Gardens, Kew, United Kingdom.http://www.kew.org/ data/grasses-db/. May 2011.

• Cope, T.A., 2002. Gramineae, tribe Andropogoneae. In: Pope, G.V. & Martins, E.S. (Editors). Flora Zambesiaca. Volume 10, part 4. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 190 pp.

• Robyns, W., 1929. Flore agrostologique du Congo Belge et du Ruanda–Urundi. Tome 1 : Maydées et Andropogonées. Goemaere, Brussels, Belgium. 229 pp.

Other references

• Akoègninou, A., van der Burg, W.J. & van der Maesen, L.J.G. (Editors), 2006. Flore analytique du Bénin. Backhuys Publishers, Leiden, Netherlands. 1034 pp.

• Clayton, W.D., 1966. Studies in the Gramineae: IX. Andropogoneae. Kew Bulletin 20(2): 257–273.

• Clayton, W.D., 1970. Studies in the Gramineae: XXI. Coelorhachis and Rhytachne: a study in numerical taxonomy. Kew Bulletin 24: 309–314.

• Clayton, W.D., 1973. The awnless genera of Andropogoneae. Studies in the Gramineae: XXXIII. Kew Bulletin 28(1): 49–57.

• Clayton, W.D., 1978. The genus Rhytachne (Gramineae). Kew Bulletin 32(4): 767–771.

• Davidse, G., 1984. A new species of Rhytachne (Poaceae: Andropogoneae) from northern south America. Brittonia 36(4): 402–405.

• Dujardin, M., 1978. Chromosome numbers of some tropical African grasses from western Zaire. Canadian Journal of Botany 56(17): 2138–2152.

• Poilecot, P., 1995. Les Poaceae de Côte d’Ivoire. Manuel illustré d’identification des espèces. Boissera 50: 1–734.

• van der Zon, A.P.M., 1992. Graminées du Cameroun. Volume 2, Flore. Wageningen Agricultural University Papers 92–1. Wageningen Agricultural University, Wageningen, Netherlands. 557 pp.

Author(s)

• 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. Rhytachne rottboellioides Desv. [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 31 March 2025.

• See the Prota4U database.