List of alismatid families

The alismatid monocots are a group of 15 interrelated families of flowering plants, named for their largest order, Alismatales. Like other monocots, they usually have a single embryonic leaf (cotyledon) in their seeds, scattered vascular systems, leaves with parallel veins, flowers with parts in threes or multiples of three, and roots that can develop in more than one place along the stems. The alismatids have adapted to thrive in oceans, temperate zones, deserts, the tropics, and even glacial regions.

Like the earliest monocots, many of the alismatid monocots are aquatic, and some grow completely submerged. Apart from the sweet-flag family of wetlands plants, all the alismatid families are in Alismatales. Some of the plants in this order are invasive aquatic weeds that can disrupt and destabilize ecosystems. Others grow in a variety of habitats, especially plants in the aroid family. This family includes the titan arum, with the world's largest unbranched inflorescence, and also the world's smallest flowering plant, duckweed.

Glossary
From the glossary of botanical terms:
 * annual: a plant species that completes its life cycle within a single year or growing season
 * basal: attached close to the base (of a plant or an evolutionary tree diagram)
 * climber: a vine that leans on, twines around or clings to other plants for vertical support
 * herbaceous: not woody; usually green and soft in texture
 * perennial: not an annual or biennial
 * woody: hard and lignified; not herbaceous

The APG IV system is the fourth in a series of plant taxonomies from the Angiosperm Phylogeny Group. In this system, the alismatids are basal within the monocots.