Zizania L.
From the Greek Zizanion, ancient Greek for a weed of grain.
Including Ceratochaete Lunell, Elymus Mitchell, Fartis Adans., Hydropyrum Link, Melinum Link
Habit, vegetative morphology. Tall, aquatic annual, or perennial. Culms 100–300 cm high; herbaceous. Culm nodes hairy, or glabrous. Culm internodes hollow. Leaves non-auriculate. Leaf blades linear-lanceolate; broad (to 3 cm), or narrow; 5–30 mm wide; flat; pseudopetiolate, or not pseudopetiolate; without cross venation (?); an unfringed membrane; 3–11 mm long.
Reproductive organization. Plants monoecious with all the fertile spikelets unisexual; without hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; female-only and male-only. The male and female-fertile spikelets on different branches of the same inflorescence (the lower, pendent branches male, the upper, ascending ones female). Plants inbreeding.
Inflorescence. Inflorescence paniculate (large, terminal); open; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-sterile spikelets. Male spikelets pendent, lemmas membranous, acute or short-awned, 5-nerved; palea 3-nerved; 6 free stamens. The male spikelets without glumes; 1 floreted. The lemmas awnless to awned. Male florets 6 staminate. The staminal filaments free.
Female-fertile spikelets. Spikelets unconventional (the glumes ‘obsolete’); 10–25 mm long (ascending); compressed laterally to not noticeably compressed; falling entire. Rachilla terminated by a female-fertile floret. Hairy callus absent.
Glumes absent (but perhaps represented by a small collar-like ridge on the pedicel). Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas acuminate into the long, acuminate lemma; not becoming indurated (papery); entire; pointed; awned. Awns 1; median; apical (from the into a long, slender awn); non-geniculate; about as long as the body of the lemma to much longer than the body of the lemma. Lemmas non-carinate; 3–5 nerved. Palea present; relatively long; 2-nerved; one-keeled. Stamens 0. Ovary glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit medium sized, or large (10–20 mm long); not noticeably compressed (cylindrical). Hilum long-linear. Endosperm hard; without lipid. Embryo with an epiblast; with a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins overlapping.
Seedling with a long mesocotyl; with a loose coleoptile (margins free, lamina well developed).
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present. Intercostal papillae over-arching the stomata; several per cell (each long-cell with one large and many small papillae). Mid-intercostal long-cells having markedly sinuous walls (the walls thin). Microhairs present; panicoid-type (tapering to base and apex); 26–36 microns long. Microhair apical cells 14–18 microns long. Microhair apical cell/total length ratio 0.48. Stomata common. Subsidiaries triangular. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Intercostal silica bodies narrowly oryzoid-type, or vertically elongated-nodular. Costal zones with short-cells. Costal short-cells predominantly paired, or neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies oryzoid; not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; with arm cells; with fusoids. The fusoids external to the PBS. Midrib conspicuous (with a characteristic system of intercellular spaces); having complex vascularization. Bulliforms present in discrete, regular adaxial groups; in simple fans, or associated with colourless mesophyll cells to form deeply-penetrating fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present.
Cytology. Chromosome base number, x = 15. 2n = 30 and 34. 2 ploid. Chromosomes ‘small’. Haploid nuclear DNA content 2.2 pg (1 species). Mean diploid 2c DNA value 4.4 pg (Z. aquatica).
Taxonomy. Bambusoideae; Oryzodae; Oryzeae.
Distribution, ecology, phytogeography. 3 species; North America and Eurasia. Hydrophytic to helophytic.
Holarctic and Paleotropical. Boreal. Indomalesian. Euro-Siberian, Eastern Asian, and Atlantic North American. Indian and Indo-Chinese. Siberian. Canadian-Appalachian and Central Grasslands.
Rusts and smuts. Smuts from Tilletiaceae and from Ustilaginaceae. Tilletiaceae — Entyloma. Ustilaginaceae — Ustilago.
Economic importance. Grain crop species: breeding of Zizania aquatica (Wildrice, long gathered from wild stands) is yielding non-shattering forms of potential economic value. Z. latifolia cultivated for its edible young shoots.
References, etc. Leaf anatomical: Metcalfe 1960 and this project.
Cite this publication as: Watson, L., and Dallwitz, M. J. (1992 onwards). ‘Grass Genera of the World: Descriptions, Illustrations, Identification, and Information Retrieval; including Synonyms, Morphology, Anatomy, Physiology, Phytochemistry, Cytology, Classification, Pathogens, World and Local Distribution, and References.’ http://biodiversity.uno.edu/delta/. Version: 18th August 1999. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1998), and Watson and Dallwitz (1994), and Watson, Dallwitz, and Johnston (1986) should also be cited (see References).