| + | Plants of mostly erect habit, aquatic, the lvs. and scapes arising from more or less tuberous or knotted rootstocks: lvs. typically arrow-shaped, with long basal lobes, but sometimes long and linear: fls. imperfect, monoecious (staminate fls. usually in the uppermost whorls) or dioecious, with 3 white broad petals and 3 small greenish sepals, the stamens and pistils numerous, the latter ripening into small achenes; infl. composed of successive whorls of 3-stalked fls. Sometimes the lvs. are floating. The number of species admitted is variable, but Buchenau in the last treatment of the genus in Engler’s Das Pflanzenreich, hft. 16 (iv. 15, 1903) describes 31. Temperate and tropical regions of the world though lacking in Afr. and Austral. |
| + | Sagittarias are mostly used for colonizing in the open, but S. montevidensis—now the most popular species—is grown in indoor aquaria or plunged in open ponds in the summer. The arrowheads are perennials of easy culture, although likely to be infested with aphis. Propagation is by division, or sometimes by seeds. |