Schoenoplectus corymbosus: a tropical Old-World sedge (Cyperaceae) discovered in Spain and Morocco Pedro Jime ´nez-Mejı ´as, Modesto Lucen ˜o and Santiago Castroviejo P. Jime´nez-Mejı´as (pjimmej@upo.es) and M. Lucen˜o, Depto de Bota´nica, Univ. Pablo Olavide, Carretera Utrera Km 1, ES41013, Seville, Spain.  S. Castroviejo, Real Jardı´n Bota´nico (CSIC), Cludio Moyano 1, ES 28024, Madrid, Spain. Schoenoplectus corymbosus is a sedge from tropical wetlands widely distributed in Pakistan, India and Africa. Recent collections confirm its presence in wetlands of southern Spain and Morocco. We consider the presence of this plant in the western extreme of the Mediterranean as a consequence of recent colonization, because it was not collected here until 1999, in spite of its mediumlarge size. Additionally, it grows in much visited areas like nature reserves (such as Don ˜ana National Park). The populations from Spain and Morocco are characterized here, a description of S. corymbosus and a key for Schoenoplectus from Europe and north Africa is supplied. Finally, the possible natural and recent colonization processes of these new populations are discussed. Schoenoplectus corymbosus (Roth ex Roem. & Schult.) J. Raynal (Cyperaceae) is a sedge of mediumlarge size from tropical areas of the Old World: Africa (Raynal 1976a, 1976b, Haines 1983, Gordon-Gray 1995, Lye 1997), Pakistan and India (Kukkonen 1998) (Fig. 1). In Africa, most populations are localized in the central, east and south regions, although the nearest localities from Spain and Morocco is the Senhadja plain (Maire 1957) in northeast Algeria, the inner Niger River Delta, in Mali, and the Nilo Delta (Ta ¨ckholm 1950). The localities shown in this paper are the first references from Europe and Morocco (Fig. 2). The west extreme of the Mediterranean Basin colonization by this species seems to be the result of a natural process without human intervention. The first specimens were collected in 1999, and since then it has been mistaken for small forms of S. lacustris. Description of the Iberian and Moroccan plants Schoenoplectus corymbosus (Roth ex Roem. & Schult.) J. Raynal in Peyre de Fabregues & Lebrun, Cat. Pl. Vasc. Niger 3:343 (1976). Isolepis corymbosa Roth ex Roem. & Schult., Syst. Veg., 2: 110 (1817) [basion.]. Scirpus corymbosus (Roth ex Roem. & Schult.) B. Heyne ex Roth, Nov. Pl. Sp.: 28 (1821), nom. illeg., non L. Isolepis inclinata Delile, Descr. Egypte, Hist. Nat. (2): 50 (1813), nom. nud. Scirpus inclinatus (Delile) Asch. & Schweinf. ex Boiss., Fl. Orient.: 381 (1882). Schoenoplectus inclinatus (Delile) Lye in Bot. Not., 124: 290 (1971). Perennial, laxly caespitose, sometimes9tussock-forming; rhizomes ca 3 mm broad. Stems (38)62150 cm 1.6 10 mm, terete, slightly striated when dry, green, curved when the nuts are ripe. Leafs reduced to sheats, pale brown, the lowest sometimes dark purple. Inflorescence an anthela, frequently simple, with 1190 spikelets, several sessile  unusually all of them  the rest grouped on pedunculated fascicles with 210 spikelets; inflorescence axis canaliculate, smooth or with a few obtuse teeth on the margin; lowest bract (18)3060(120) 0.91.5 mm, erect, terete, as long as or longer than the inflorescence; spikelets 48 mm, ovate to ovatelanceolate, (3)1220(30) flowered, usually pseu- doviviparous. Glumes 2.73.5 1.21.8 mm, ovate, with a short mucro 0.10.3 mm; smooth, with glabrous margins, denticulate to the apex, which is not emarginate; pale brown, scarious to the base, 1-nerved, usually with a green central band and narrow scarious margins, sometimes absent. Anthers 1.51.8 mm, yellow, with a reddishbrown mucro (0.15)0.20.3 mm, smooth or laxly scabrid to the apex. Style 3-fid. Achenes (1.3)1.42(2.2) (0.7)1 1.5 mm, obovate, broadly trigonous, with small irregularly distributed wrinkles, visible under amplification, yellowish when immature, dark brown to blackish when ripe, shining; perianth bristles absent. The studied samples do not show any differences in morphological features compared to the studied African and Asian samples. The infrageneric position of this taxon is uncer- tain. Beetle (1942) placed it in sect. Actaeogeton, while Nordic Journal of Botany 25: 7074, 2007 doi: 10.1111/j.2008.0107-055X.00007.x, # The Authors. Journal compilation # Nordic Journal of Botany 2007 Subject Editor: Torbjo ¨rn Tyler. Accepted 1 October 2007 70