Callitriche brutia var. hamulata

(Kützing ex W. D. J. Koch) Lansdown

Watsonia 26: 113. 2006.

Common names: Narrowleaf water-starwort
Basionym: Callitriche hamulata Kützing ex W. D. J. Koch Syn. Fl. Germ. Helv., 246. 1837
Synonyms: C. intermedia Hoffmann C. intermedia subsp. hamulata (Kützing e× W. D. J. Koch) A. R. Clapham
Treatment appears in FNA Volume 17. Treatment on page 50. Mentioned on page 51.

Leaves connate at base, ± linear, tapering strongly from near base or spatulate, 5.4–18 × 0.3–3 mm, 1+-veined. Stem and leaf scales present. Inflorescences: bracts caducous. Pedicels 0 mm, rarely less than 2 mm in fruit. Flowers usually solitary; styles reflexed, appressed to ovary; pollen colorless. Schizocarps 1.1–1.5(–1.6) × 1.1–1.4 mm, as long as wide; mericarps blackish, not swollen, winged throughout, wings straight, 0.03–0.3 mm wide. 2n = 38.

Phenology: Flowering Jul–Sep.
Habitat: Fast-flowing streams, backwaters, lakes, pools.
Elevation: 0–1600 m.


Greenland, B.C., Oreg., Wash., Europe.


Variety hamulata is considered native in Greenland and is introduced in other parts of the flora area; the earliest specimen of var. hamulata known from western North America is from Oregon in 1956 (Steward 7238, MO).

Selected References


Lower Taxa

Richard V. Lansdown +
(Kützing ex W. D. J. Koch) Lansdown +
Callitriche hamulata +
Narrowleaf water-starwort +
Greenland +, B.C. +, Oreg. +, Wash. +  and Europe. +
0–1600 m. +
Fast-flowing streams, backwaters, lakes, pools. +
Flowering Jul–Sep. +
C. intermedia +  and C. intermedia subsp. hamulata +
Callitriche brutia var. hamulata +
Callitriche brutia +
variety +