Nordic Journal of Botany Accepted 10-11-2002 Nord. J. Bot. 22(5) 2002 1 NJB-22-52 Juncus uruguensis – a member of the section Juncotypus (Juncaceae, Juncus subg. Agathryon ) Drábková, L. & Kirschner, J. 2003. Juncus uruguensis – a member of the section Juncotypus (Juncaceae, Juncus subg. Agathryon). – Nord. J. Bot. 22: 000-000. ISSN 0107-055X. Anatomy and morphology of Juncus uruguensis were studied in order to determine the sectional position of the species. Leaf anatomy, a decisive criterion for sectional classification in the subg. Agathryon, shows that the species should be placed in the sect. Juncotypus, not in the sect. Steirochloa. L. Drábková and J. Kirschner, Institute of Botany, Dept. of Taxonomy, Academy of Sciences, Zámek 1, 252 43 Prùhonice, Czech Republic. E-mail: drabkova @ibot.cas.cz / kirschner@ibot.cas.cz. Lenka Drábková and Jan Kirschner Introduction Juncus uruguensis (Fig.4) is a peculiar taxon distrib- uted from south-central Bolivia to C and E Argen- tina (provinces of Salta, Mendoza, Buenos Aires and Entre Ríos) and Uruguay (see also Herter 1930, 1943, Barros 1953, Balslev 1996, and J. L. Novara, unpubl.; Fig. 5). In spite of its name, the type local- ity, Conception del Uruguay is situated in Argen- tina, province of Entre Ríos, near the border with Uruguay (the type collection: P. G. Lorentz 1126, GOET). Juncus uruguensis was described by A. Grisebach in 1879. Description: Caespitose perennials 20-60 cm tall, with rhizome 1-3 mm in diameter, densely branched or creeping with short internodes. Stems erect, rigid, 1-2.5 mm in diameter, with 10-25 longitudinal ridges, ± bulbous at base, the thickening covered with brown to castaneous scales. Cataphylls are 0-2 per stem, to 7 cm long, blade rudimentary, to 5 mm long, leaves 1-2 per stem, 10-25 cm long, usually to half as long as stem, sheaths 3-11 cm long, with scariose margins and auricles 0.5-1.0 mm, blades fili- form, 0.7-2.0 mm wide, adaxial surface reduced, leaf elliptic in T S., ± striate, adaxial enlarged (bulliform) cells absent. Lower bract is 1.5-4.5 cm long, ±shorter than or equalling inflorescence, with well developed sheath and short blade. Inflorescence is ± terminal or ± pseudolateral, compound, 1.5-7 × 1.5-3 cm, 15- 100-flowered, of several unilateral, clustered cymes (drepania). Bracteoles are 1.5-2.0 mm long. Tepals are unequal, lanceolate, acute, green, later bright castaneous, margins scariose, outer tepals 4-5 mm long, central band thicker, extending to a mucro, in- ner ones c. 3.5 mm long. Stamens are 3, 1.5-2.5 mm long; anthers 0.8-1.5 mm, longer than filaments to 1 mm long. Capsule is ellipsoid, obtuse to truncate, trigonous to trilobed in T.S., ± trilocular, 3.5-4.0 × 1.5-2.0 mm, castaneous, glossy, thick-walled, ± shorter than perianth. Seeds are ellipsoid, apiculate, 0.3-0.4 × 0.15-0.2 mm, rugose or ridged, brown; ap- pendages absent (Kirschner et al. 2002, in press.). In the protoloque, Grisebach (1879) compared the new species with Juncus compressus “Kunth”, a name referable to J. balticus subsp. mexicanus (Roemer et Schultes) Snogerup of the section Juncotypus (=subg. Genuini). Later authors often emphasized the intermediate position of J.