23. Cyperus arenarius Retz., Observ. Bot. . 4: 9. 1786; C.B.Clarke in Hook.f., Fl. Brit. Ind. 6: 86. 1893; R.R.Stewart, l.c. 86. 1972; Kukkonen in Rech.f., l.c. 114.
C. persicus Boiss. & Hohen., in Boiss., Diagn. Pl. Or. Nov. 13: 39. 1854. C. persicus Steud. & Boiss., in Steud., Syn. Pl. Cyperac.: 28. 1855; Koyama in Dassanayake & Fosb., Fl. Ceylon 5: 210, Fig. 13. 1985.
Perennial, 6-30 cm. Rhizome long creeping, deep in sand, c. 1 mm diam. Roots thin, not tomentose. Stem c. 1 mm diam., almost terete, smooth. Leaves c. equalling the stem; sheaths 20-40 mm, strongly nerved, rigid, with brown veins, disintegrating into fibres with age, mouth margin straight; ligule 0; blades c. 1 mm wide, stiff, curved, greyish green, semi-circular in transverse section, margins slightly scabrous, apex flat, blunt or acute, slightly scabrous. Inflorescence c. 20 mm diam., capitate, with 5 to more than 20 spikes, seldom with some elongated branches; bracts 1-2 foliose, up to 50 (100) mm, rigid, sheath-less, one often as continuation of stem; spikes 8-20 mm, ovoid, compressed, glumelike bracts c. 5 mm, glume-like prophyll 4 mm, widely ovate, with scarious margins, blunt; glumes 14-24, closely imbricating, caducous, 4-5 mm, cymbiform, with rounded back, pale brown, mucronate, sides with c. 6 obscure nerves, which often reddish brown, margins scarious; rachis zigzagging, c. 1 mm wide, internodes c. 0.5 mm, margins sharp, hardly winged. Stamens 3. Nut 1.5-1.7 x c. 1.3 mm, obovoid, plano-convex, compressed, brown or dark brown, almost smooth, glossy.
Fl. Per.: February - April. According to Bhandari (Fl. Indian Desert, 1990) flowering and fruiting from September to December (October-November by Cooke, 1908).
Type: India: Tamil Nadu, "In arena volatili Indiae orientalis", Tranquebar, J.G. König (LD!).
Coastal sands and sandy river beds; Distribution: From W coasts of Persian Gulf to W and E Coasts of India and Sri Lanka; (E.G.Camus in M.H.Lecomte, Fl. générale Indoch. 7: 19-20. 1912); Vietnam, "Cochin China", Mekong delta; obviously introduced to S. Australia and Durban, S. Africa.
Inland records by R.R.Stewart (1972) need to be confirmed.