Rhytachne rottboellioides (PROTA)
- Protologue: Ham., Prodr. Pl. Ind. Occ.: 12 (1825).
- Family: Poaceae (Gramineae)
- Chromosome number: n = 16
- 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.
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.
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.
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.
Rhytachne rottboellioides only grows wild.
As Rhytachne rottboellioides is extremely widely distributed and sometimes weedy, its great genetic variability does not seem to be in danger of genetic erosion.
Rhytachne rottboellioides is likely to remain a fodder grass of moderate quality and of local interest only as a source of material for wickerwork.
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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. 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 5 March 2020.
- See the Prota4U database.