FLORA OF ICELAND elements: Equisetum arvense, Field Horsetail, Klóelfting

Equisetum arvense; The Field Horsetail is very common. It grows both in disturbed areas, like roadsides and dumps as well as in natural areas almost everywhere in Iceland. The pale, slightly reddish, fertile stems appear first in early spring, well before the vegetative stems appear.
Compared to similar species the length of the first segment of side branches compared to corresponding segment above the branching node is longer. The number of sheath-teeth on the main stem at the branching node is 10-12 but only three along branches. The teeth on the main stem are black without membranous margins, while they are grayish white to green on the side-branches. The side branches grow upwards.
Like many other horsetails the plants of this species has a high level of silica. For this reason organic farmers make extracts of this plant which is sprayed on crops. The silica protects crops from fungi-diseases. It is member of the Equisetaceae, the Horsetail family. The Icelandic name is Klóelfting.