198. Zannichelliaceae Dumortier
Horned- pondweed Family
Robert R. Haynes; C. Barre Hellquist
Herbs, annual [perennial], not rhizomatous, caulescent; turions absent. Leaves alternate, opposite, or pseudowhorled, often all on same plant, submersed, sessile; sheath not persisting longer than blade, not leaving circular scar when shed, ligulate, not auriculate; blade linear; intravaginal squamules scales, 2. Inflorescences axillary, cymes, without subtending spathe, sessile. Flowers uniasexual, staminate and pistillate flowers on same plant; subtending bracts absent; perianth absent. Staminate flowers: stamens 1; anther dehiscing longitudinally; pollen globose. Pistillate flowers: pistils (1--)4--5(--8), distinct, short-stipitate; ovules pendulous, anatropous. Fruits drupaceous. Seeds 1; embryo curved.
Genera 4, species 10--12 (1 genus, 1 species in the flora): nearly worldwide.
SELECTED REFERENCES
Campbell, D. H. 1897. A morphological study of Naias and Zannichellia. Proc. Calif. Acad. Sci., ser. 3, 1: 1--70. Haynes, R. R. and L. B. Holm-Nielsen. 1987. The Zannichelliaceae in the southeastern United States. J. Arnold Arbor. 68: 259--268. Posluszny, U. and P. B. Tomlinson. 1977. Morphology and development of floral shoots and organs in certain Zannichelliaceae. Bot. J. Linn. Soc. 75: 21--46. Taylor, N. 1909. Zannichelliaceae. In: N. L. Britton et al., eds. 1905+. North American Flora.... 47+ vols. New York. Vol. 17, pp. 13--27. Tomlinson, P. B. and U. Posluszny. 1976. Generic limits in the Zannichelliaceae (sensu Dumortier). Taxon 25: 273--279.
