11. Cyperus esculentus Linnaeus, Sp. Pl. 1:45. 1753; Boiss., Fl. Or. 5: 377. 1882; C. B. Clarke in Hook.f., Fl. Brit. Ind. 6: 616. 1893; R.R.Stewart, l.c. 88; Kukkonen in Rech.f., l.c. 98.
C. aureus Tenore, Fl. napol. Prodr. "I.(1811) VIII." Holm & al., World's Worst Weeds: fig. 46. 1977. Haines & Lye, Sedges and Rushes E. Afr.: figs. 372 & 373. 1983.
Perennial, 30-80 cm. Base of stem slightly swollen, with stolons to c. 20 cm, tuber up to 15 mm diam., round or elongate, rooting, covered by greyish-brown scales. Stem 2-3 mm diam., trigonous, smooth. Leaves shorter than stem; sheaths 50(-100) mm, yellowish or greyish brown, sometimes with reddish tint, mouth margin nearly straight or lingulate; blades to 30(-60) cm, to 5 mm wide, yellow-green, keeled, margin slightly revolute, smooth or towards apex scabrous, apex acute, trigonous, scabrous. Inflorescence an anthelodium, primary rays to more than 10, to 80 mm; lowest 2-3 bracts leaf-like, up to 30 cm, 5 mm wide, sheathless; primary branches end with often more than 20 spreading spikes in irregular spiral, but small secondary anthelodia frequent. Spikes up to 15 x c. 1.5 mm, elongating after flowering, with 5-12 flowers; glume-like bract c. 2 mm, glume-like prophyll two-veined, c. 1.5 mm, base swollen; rachis compressed, slightly zigzagging, internodes c. 1 mm, winged; glumes 2-2.5 mm, cymbiform, blunt, yellow-brown, with 5-9 conspicuous veins, mid-vein strong, with short mucro below glume apex, margins scarious. Nut c. 1.5 mm, ovoid or obovoid, obtusely trigonous, yellow-brown or dark-brown, surface reticulate-papillose.
Fl. Per.: April-July.
Lectotype: Cyperus rotundus, esculentus angustifolius Bauhin, Theatr. Bot. 222, ic. 1658, lectotype selected by D. Simpson in Jarvis & al., Regnum Veg. 127: 41. 1993.
R. R. Stewart (l.c. 88) has reported it from Hazara, Jhelum and Sind.
Sandy river-sides, humid forests; irrigated fields; Distribution: Concentrated in tropical and subtropical Africa, but a weed in all continents; formerly cultivated, especially in the Mediterranean, for edible tubers rich in carbohydrates and oil (earth almond, chufa).
Often mixed with pale coloured races of the polymorphic C.rotundus, but stolons more slender and tubers more regularly zoned, glumes less closely imbricating and glume side with several distinct, pale nerves.