23. CLADIUM P. Browne, Civ. Nat. Hist. Jamaica. 114. 1756.
Twig-rush, sawgrass, marisque [Greek clados, branch, referring to the highly branched inflorescences]
Gordon C. Tucker
Mariscus Scopoli 1754, name rejected, not Vahl 1805, name conserved
Herbs, perennial, cespitose or not, rhizomatous or stoloniferous. Culms solitary or not, terete or rounded-trigonous, usually 70+ cm. Leaves cauline; ligules absent; blades flat to involute. Inflorescences terminal or some lateral, corymbose or subcapitate, conspicuously branched; spikelets 100–1000+; involucral bracts 3–4+, spreading, leaflike. Spikelets: scales 5–6, spirally arranged, proximal 1–3 scales empty, distal 3–4 scales each subtending flower. Flowers bisexual or staminate; perianth absent; stamens 2–3; styles linear, 3-fid, base persistent, somewhat thickened. Achenes terete. x = 20.
Species 4 (3 in the flora): North America, Mexico, West Indies, Central America, South America, Eurasia, Africa, and Australia.
Cladium is here accepted in the strict sense, i.e., consisting of four species: C. mariscus, of the Old World, and three species treated below. The genus had been treated in a broader sense, including Machaerina Vahl (G. Kükenthal 1942). Later studies (cited by G. C. Tucker 1987) argue against such a broad circumscription of the genus. Machaerina was excluded by M. T. Strong (1997). Species of Cladium consistently differ from those of Machaerina in their smaller, less differentiated embryos and anisobilateral leaves with inverted bundles (illustrated by C. R. Metcalfe).
According to G. Kükenthal (1942), Cladium mariscus comprised three subspecies: C. mariscus subsp. mariscus of Europe and Asia; C. mariscus subsp. jamaicense (Crantz) Kükenthal of the Western Hemisphere, Africa, and Hawaii; and C. mariscus subsp. intermedium Kükenthal of Australia. He synonymized C. californicum under C. mariscus subsp. jamaicense. Most American authors have treated C. jamaicense as distinct from the Eastern Hemisphere C. mariscus, a view followed here with some trepidation. Resolution of this taxonomic problem is well beyond the scope of this flora. The culms and leaves of Cladium mariscus are gathered and used in the manufacture of paper products in the Danube Delta, Romania.
SELECTED REFERENCES
Kükenthal, G. 1942. Vorarbeiten zu einer Monographie der Rhynchosporoideae. XI. 10. Cladium Crantz [sic]. Repert. Spec. Nov. Regni Veg. 50: 1–17, 139–193. McVaugh, R. 1993. Cladium. In: R. Vaugh and W. R. Anderson, eds. 1974+. Flora Novo-Galiciana: A Descriptive Account of the Vascular Plants of Western Mexico. 8+ vols. Ann Arbor. Vol. 13, pp. 267–270. Raynal, J. 1972. Notes cypérologiques: 17. Révision des Cladium P. Browne s. lat. (Cyperaceae) de Madagascar et des Mascareignes. Adansonia, n. s. 12: 103–112.
