Equisetum hyemale; The Rough Horsetail is common on Iceland. It grows both in lowland and highland regions, where ever conditions are reasonably favorable for plant growth. However, it is not a bog plant like some other horseteils. This horsetail can easily be distinguished from others: it is a totally unbranched-stem species which are far thicker in than any other species. I have also noticed that this plant is used in revegetation programmes on barren wind-eroded land around Mývatn. Similar species can be identifies by the following characteristics:
- E. palustre: marsh horsetail: short side branches, terminal cones not pointed, about 13 dental points on stem-sheaths.
- E. fluviatile: water horsetail: no side branches, terminal cones not pointed, about 14 dental points on stem-sheaths.
- E. variegatum: variegated horsetail: no side branches, terminal cones pointed, about 5-8 dental points on stem-sheaths
- E. hyemale: rough horsetail: no side branches, about 20 dental points on stem-sheath - but very tiny: the sheaths seems almost round. Much thicker stems than any other horsetail on Iceland
