Epilobium hornemanni; The Hornemann's Willowherb is a perennial short herb, growing up to 15 cm. Like all other willowherbs it has the long fruits below the flower calyx and corolla.
- The leaves are ovate in shape. Their margins are minutely dentate and the apex is blunt and round. The stems rise from short rootstocks.
- The corolla is bluish-red while the calyx and the fruit are red.
- It is a common species growing along cold-water creeks and moist grounds. It is rather rare in the southern regions of Iceland.
- It is a member of the Onagraceae, the Willowherb family. The Icelandic name is Heiðadúnur.
The species is very similar to the Chickweed Willowherb (Epilobium alsinifolium). The best way to tell them apart is to look at the leaves: The Chickweed Willowherb has leaves with more coarsely dentated margins. The margins are more undulate between the teeth, where the leaf-margins of the Hornemann's Willowherb are only minute dentated, hardly undulate. A second difference is the more pointed apex of the leaves of the Chickweed Willowherb, where they are more rounded in the Hornemann's Willowherb.