5.05 ZIZANIOPSIS Döll & Asch.
Edward E. Terrell

Plants perennial or annual; aquatic, rooted and emergent; rhizomatous; monoecious. Culms 1–4 m, erect or decumbent, sometimes rooting at the nodes. Leaves basal and cauline; sheaths open, somewhat laterally compressed; ligules scarious; pseudopetioles absent; blades flat or folded at the base, lanceolate. Inflorescences terminal panicles, staminate and pistillate spikelets on the same branches, staminate spikelets proximal, pistillate spikelets distal; disarticulation beneath the spikelets; pedicel apices cupulate. Spikelets unisexual, laterally compressed to subterete, lemma margins not clasping the paleas, with 1 floret. Glumes absent; calluses glabrous. Staminate lemmas membranous, 5–7-veined, acuminate or terminally awned; paleas similar to the lemmas, 3-veined; lodicules 2; anthers 6. Pistillate lemmas membranous, 7-veined, terminally awned; paleas similar to the lemmas, 3-veined, awned or unawned; styles 2, bases fused, stigmas terminally exserted, plumose. Fruits achenes, ellipsoid or obovoid, beaked by the persistent style base; pericarps shell-like, partially free from the seed, smooth, coriaceous or crustaceous; seeds oblong, subterete, or 2-angled; embryos basal; hila linear. x = 12. Name based on the generic name Zizania and the Greek opsis, ‘appearance’, alluding to the similarity to Zizania.

Zizaniopsis grows from the southern United States to Argentina. All of its five species grow in wet habitats. Only Zizaniopsis miliacea is native to and found in the Flora region.

SELECTED REFERENCES Fox, A.M. and W.T. Haller. 2000. Production and survivorship of the functional stolons of giant cutgrass, Zizaniopsis miliacea (Poaceae). Amer. J. Bot. 87:811–818; McVaugh, R. 1983. Flora Novo-Galiciana: A Descriptive Account of the Vascular Plants of Western Mexico, vol. 14; Gramineae (series ed. W.R. Anderson). University of Michigan Press, Ann Arbor, Michigan, U.S.A. 436 pp.; Terrell, E.E. and H. Robinson. 1974. Luziolinae, a new subtribe of oryzoid grasses. Bull. Torrey Bot. Club 101:235–245.

1. Zizaniopsis miliacea (Michx.) Döll & Asch.
Giant Cutgrass, Water Millet

Plants perennial; rhizomatous, rhizomes to 1.5 cm thick. Culms 1–4 m tall, to 3.5 cm thick, erect or decumbent, glabrous, readily rooting at the nodes when decumbent and producing leafy buds. Sheaths thick, glabrous; ligules to 2 cm, glabrous; blades to 1 m long, 6–30 mm wide, sometimes scabrous, bluish-green, margins scabrous. Panicles to 80+ cm long, usually 4–20 cm wide, open; pedicels to 10 mm long, apices 0.1–0.4 mm wide. Staminate lemmas 5–10 mm, lanceolate to elliptic, glabrous, acuminate or awned, awns to 2 mm; paleas acuminate or awned, awns to 1 mm; anthers 2.5–5 mm. Pistillate lemmas 4–8 mm, ovate or elliptic, awned, awns to 9 mm; paleas caudate-acuminate or awned, awns to 1 mm; style bases 1–3 mm, stigmas 2–6 mm, conspicuously exserted. Achenes 2.5–4 mm long, 1–2 mm wide, ellipsoid or obovoid, smooth, lustrous, beaked by the persistent style base. 2n = 24.

Zizaniopsis miliacea grows in shallow, fresh- or brackish-water marshes, swamps, streams, lakes, and ditches. It is most common on the eastern coastal plain of the United States, extending south to Florida and west to Illinois, Oklahoma and Texas. It has also been reported growing as a disjunct in central Mexico (McVaugh 1983).

Fox and Haller (2000) found that decumbent flowering culms readily produce roots and axillary shoots at the nodes. The decumbent culms act as functional stolons, allowing for rapid colonization; thus plants become established up to 3–4 m away from the parent plant.