The arrowgrass family (Juncaginaceae) is a family of herbaceous plants whose leaves are grass-like and shaped somewhat like an arrowhead. The arrowgrass family has four genera: Scheuchzeria with two species; Thrighlochin with 12 species; Maundia with one species; and Tetroncium with one species.
All species in the arrowgrass family grow in wet or moist habitats in temperate and cold regions of the world. Many species grow in fresh water and are common in sphagnum bogs. Other species grow in brackish (semi-salty) water.
All plants in this family have thin, grass-like leaves that are flat, linear, and smooth. They have a specialized underground stem, referred to as a rhizome. The leaves and roots arise from the rhizome. The roots of some species are fat and tuberous. Most species are perennial, in that they maintain leaves all year round.
The flowers of all species are small and inconspicuous, with clusters of individual flowers arising from an erect stalk. This inflorescence is referred to as a spike or raceme. The flowers are symmetrical, and the different parts of the flowers occur in threes or in multiples of three. Some species have bisexual (monoecious) flowers, in that male and female organs occur on the same flower. Other species have unisexual (dioecious) flowers, with male and female organs occurring in different, separate flowers. The flowers of all species are wind-pollinated.
The fertilized flowers give rise to fruits, referred to as follicles. A follicle is a dry fruit that splits along a suture on one side to release the seed(s). The follicles of plants in the arrowgrass family have one or two seeds. Each embryonic seed has one cotyledon (seed leaf).
The plants of the arrowgrass family are not of great economic significance to humans. However, the leaves or rhizomes of some species have been traditionally eaten by some aboriginal peoples of North America and Australia.