Horned-pondweed [for Gian Girolamo Zannichelli, 1662--1729, Venetian apothecary and botanist]

Roots single or in pairs at nodes. Leaves: blade entire, veins 1[--3], nearly terete. Inflorescence usually of 2 flowers, 1 staminate, 1 pistillate. Flowers short-pedicellate. Staminate flowers: anthers 4-loculed. Pistillate flowers: pistils surrounded proximally by membranaceous envelope; stigma asymmetrically funnel-shaped. Fruits: convex margin minutely dentate; endocarp often coarsely papillose (visible after decay of outer fruit wall); stipe developing into podogyne (stalk supporting pistil).

Species ca. 5 (1 in the flora): nearly worldwide.

SELECTED REFERENCE

Van Vierssen, W. 1982. The ecology of communities dominated by Zannichellia taxa in western Europe. I. Characterization and autecology of the Zannichellia taxa. Aquatic Bot. 12: 103--155.

Lower Taxon

• Zannichellia palustris Linnaeus