Callitriche heterophylla
Callitriche heterophylla, commonly called twoheaded water-starwort, is a species of flowering plant in the family Plantaginaceae. It is native to North America, where it found in the north from Greenland to Alaska, south to Mexico. It is widespread in the United States. Its natural habitat is in a wide variety of wetlands, including ponds, streams, and mudflats. It is typically found in areas of still or slow moving water.
Callitriche heterophylla is an aquatic plant, growing almost entirely submerged except for its floating stem tips. It produces minutely small flowers throughout the growing season.
Taxonomy
Callitriche heterophylla was scientifically described and named in 1813 by Frederick Traugott Pursh. It is part of the genus Callitriche which is classified in the family Plantaginaceae. According to Plants of the World Online it has eleven heterotypic synonyms.| Name | Year | Rank | Notes |
| Callitriche anceps Fernald | 1908 | species | |
| Callitriche asagraei Hegelm. | 1864 | species | |
| Callitriche bolanderi Hegelm. | 1868 | species | |
| Callitriche brevifolia Pursh | 1813 | species | |
| Callitriche cruciata Raf. | 1811 | species | nom. utique rej. |
| Callitriche heterophylla subsp. bolanderi Calder & Roy L.Taylor | 1963 | subspecies | |
| Callitriche heterophylla var. bolanderi Fassett | 1951 | variety | |
| Callitriche ovata Raf. | 1811 | species | nom. utique rej. |
| Callitriche palustris var. bolanderi Jeps. | 1936 | variety | |
| Callitriche spuria Raf. | 1808 | species | nom. utique rej. |
| Callitriche tuerckheimii Urb. | 1912 | species |