Callitriche hamulata; The Intermediate Water-starwort is a rather common water plant which grows in stagnant or slowly flowing water. It is best characterized from other water-starworts by heaving both submerged and floating leaves, but they are not so different. The floating leaves are just a little wider than the submerged leaves (where in other species floating leaves are missing or much broader) and they also have a double pointed apex. A very similar species is Callitriche brutia: Pedunculate Water-starwort. This is a rare species found only in a few localities in Western Iceland. The differentiating characteristic is the stalked flower/fruit. Some botanists consider "hamulata" to be a subspecies of "brutia".
Traditionally they have been classified in their own family: starwort family (Callitrichaceae) but recently they have been included in the plantain family (Plantaginaceae). The Icelandic name of this species is Síkjabrúða.