Cladium
Civ. Nat. Hist. Jamaica, 114. 1756.
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.
Distribution
North America, Mexico, West Indies, Central America, South America, Eurasia, Africa, and Australia.
Discussion
Species 4 (3 in the flora).
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
Lower Taxa
Key
| 1 | Culms 0.3–1 m × 1–2 mm; leaves 2–3 mm wide, conduplicate to subinvolute, margins ± smooth; inflorescences 15–25 cm, with 1st and 2d order branches only. | Cladium mariscoides |
| 1 | Culms 1–3 m × 5–10 mm; leaves 5–20 mm wide, flat to broadly V-shaped, margins harshly scabrid; inflorescences 30–50 cm, with 3d and 4th order branches. | > 2 |
| 2 | Spikelets mostly in groups of 2–3(–6); inflorescences with 3d and 4th order branches; culms 1–3 m, coastal se United States. | Cladium jamaicense |
| 2 | Spikelets mostly in groups of 3–6; inflorescences rarely with 4th order branches; culms 1–2 m; sw United States. | Cladium californicum |