Lycopodium annotinum; The Interrupted Clubmoss can easily be recognized from all other common Icelandic clubmosses by the rather glossy leaves spreading from the stems. It is most common in the northern, north-western and north-eastern coastal regions. On Iceland it is known as Lyngjafni.
How to recognize common Iceland clubmosses:
1) No trailing stems and no "cones on top of stems", leaves needle-shaped with smooth margins :
Lycopodium selago (= Huperzia selago), fir clubmoss
else: go to 2)
2) No trailing stems but sporophyls (leaves with spore-forming organs in the axis of leaf and stem) on top of stems, leaves are toothed:
Selaginella selaginoides, Lesser Clubmoss
else: go to 3)
3) Long prostrate stems ("runners") and sporophyllia on top of ascending brances;
3a) leaves of ascending branches pressed on the stem:
Lycopodium alpinum, Alpine Clubmoss
3b) leaves of ascending branches spreading from stem:
Lycopodium annotinum, Interrupted Clubmoss; this card
Very rare on Iceland is Lycopodium clavatum - of western Europe. It is much like Lycopodium annotinum but characteristically has a stem segment between the vegetative parts and the sporophyl-bearing part which has very small leaves, making this intersegment stem look almost nude. Split on top of this segment are two sporangial stems (hence the name clavatum).