Common Name: HORNWORT FAMILY
Habit: Perennial herb, submersed aquatic; overwintering on bottom as detached, dense shoot tips (winter buds); roots 0; monoecious; water-pollinated. Stem: flexible with water currents, internodes clustered near tip. Leaf: whorled, generally compound, forked; segments linear, toothed; stipules 0; petiole 1--2 mm, translucent. Inflorescence: reduced axillary cymes generally near shoot tips, +- sessile, 1--several per node, generally staminate below, pistillate above, or sometimes mixed at a node; flowers 1--3 per cyme but appearing to be 1 subtended by calyx-like whorl of 8--15 bracts, bracts linear, leaf-like, fused at base, toothed at tip, persistent in fruit. Flower: unisexual; perianth 0; staminate round-topped, stamens 3--50, spirally arranged, anthers +- sessile, exserted from bracts, pollen shed underwater; pistillate of 1 simple, ovoid pistil, ovary superior, chamber 1; placenta pendulous; style elongate, spine-like, with decurrent groove; stigma pocket-like, at style base; ovule 1. Fruit: achene, tubercled or not, spines 0 or elongate, basal, facial, marginal or stylar; lateral margin winged or not.
Genera In Family: 1 genus, 6 species: +- worldwide.
eFlora Treatment Author: Donald H. Les
Scientific Editor: Thomas J. Rosatti.