Bolander'S Water-Starwort

Callitriche heterophylla exhibits a unique morphological structure with both submerged and terrestrial leaves. The submerged or floating leaves are obovate or oblong, with a broadly spathulate blade that tapers abruptly or gradually into a petiole. These leaves often form a floating rosette at the apex. The terrestrial leaves are much narrower and linear. The plant typically produces solitary flowers or occasionally a combination of male and female flowers in the leaf axils. The flowers are small, with caducous bracts and either persistent or caducous styles. The fruit is subsessile, rounded, and black when mature, measuring between 0.4 and 1.2 mm in length and width, and is not winged except possibly at the apex. The anthers are quadrilocular, and the pollen is yellow. This species is easily distinguished by its small, rounded, unwinged, and black fruit, which is a key identifying feature.

This species is primarily found in wetland habitats such as ponds, streams, and mudflats. It prefers still or slow-moving water and is often associated with shallow aquatic environments. Callitriche heterophylla is adaptable and can be found in both freshwater and brackish conditions, though it is more commonly observed in freshwater ecosystems. Its distribution spans a wide range of latitudes, from the Arctic regions of Greenland and Canada to temperate and subtropical zones in the United States and Mexico.

Callitriche heterophylla is not commonly cultivated for ornamental or agricultural purposes. However, it can be grown in controlled aquatic environments such as water gardens or wetland restoration projects. It requires a consistently moist to submerged substrate and thrives in still or slow-moving water. The plant is relatively hardy and can tolerate a range of water conditions, including varying levels of salinity. Propagation is typically through seed or vegetative means, though detailed cultivation techniques are not widely documented due to its limited horticultural use.

Callitriche heterophylla has no significant economic or agricultural use. It is occasionally used in ecological restoration projects to stabilize wetland soils and provide habitat for aquatic organisms. The plant may also serve as a food source for certain aquatic herbivores. Due to its small size and specific habitat requirements, it is not commonly utilized in traditional or modern medicine. Its primary value lies in its ecological role within wetland ecosystems.