1. Eichhornia crassipes (Mart.) Solms (water hyacinth)

Pl. 189 l; Map 763

Plants annual (perennial farther south). Stems stout. Leaves clustered at the stem tips, thick, shiny, the petioles 3–17(–35) cm long, inflated or bulbous‑swollen around the middle, the blades 3–10 cm wide, kidney‑shaped to nearly circular. Stipules absent. Inflorescences dense panicles, sometimes reduced to spikes, usually glandular puberulent, long‑stalked and extending past the leaves. Perianth fused below the middle, more or less 2‑lipped, the lobes 3–4 cm long, lilac to blue or white, the upper middle lobe with a yellow area near the base. Stamens 6, 3 shorter and 3 longer, the filaments attached near the middle of the anthers. Fruits slender capsules to 2 cm long, enclosed by the persistent perianth tube. Seeds numerous, about 1 mm long, with about 10 longitudinal ribs. 2n=32. July–August.

Introduced, escaped from horticultural plantings in southeastern Missouri and rarely farther north (native to tropical South America, widely naturalized in warm parts of the world). Floating aquatics in ponds and sloughs.