Myriophyllum alterniflorum, DC.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1981, Flora Europaea. Volume 2. Rosaceae to Umbelliferae, Cambridge University Press : 312

3. M. alterniflorum DC. in Lam. & DC., Fl. Fr. ed 3, 5: 529 (1815).

Stems up to 120 cm; turions absent. Leaves 1-2-5 cm, (3-)4 in a whorl, about equalling the internodes; segments 6-18. Spike up to 3 cm, with apex drooping in bud. Male flowers solitary or in opposite pairs, usually with rudiments of carpels. Female flowers whorled at base, in groups of 2-4 or solitary above. Bracts leaf-like, longer than the flowers at the base of the inflorescence, entire and shorter than the flowers in upper part. Hermaphrodite flowers rare. Petals 2-5 mm, yellow with red streaks. Stamens 8. Fruit 1*5-2 xc. 1-5 mm, subcylindrical, finely tuberculate. 2« =14. Mainly in W., N. & C. Europe, but extending south-eastwards to Sicilia & W. Ukraine. Az Be Br Co Cz Da Fa Fe Ga Ge Hb He Ho Hs Is It Lu No Po Rs (N, C, W) Sa Si Su.