Carex lyngbyei; the Lyngbye's Sedge is one of the larger sedges on Iceland. According to sources, it can grow to more than a meter high. I have noticed that on Iceland it rarely exceeds 75cm. It is a non-cespitose sedge that spreads through stolons.
- The leaves are broad (usually over ½cm) and long. Leaves and inflorescence bracts often exceeds the culms. The sheath of the basal leaves are red-brown. They have recurved edges and their apex's are obtuse.
- The inflorescence is made up of a few (1-3) terminal male spikes and below these are a few female spikes. It is not uncommon for the highest female spikes to have male flowers on top too. Quite conspicuous are the long acutely pointed scales on the female spikes. They are less pointed on the male spikes. The scales are very dark with a slightly less dark midrib on both spike genders. However, from personal observations it seems to me that the lighter midrib is more pronounced on the male-spike scales (but this may not be true). The female flowers have two stigma's. The elliptic, more or less lens-spaped utricles have only short beaks. Both male and female spikes are on long slender drooping peduncles. Especially the female spikes bend down completely when ripe.
- It commonly grows in marsh lands and lake margins in lowland regions of Iceland. It also grows in the pacific coastal regions of North America. Strangely, it is known there as a plant of salt marshes. Although I have seen it on Iceland on grasslands prone to inundation by the sea (like Rauðsandur NW Iceland), the species on Iceland is more known from fresh water marshes and lakes. However, it does seem to prefer nutrient/iron rich conditions.
- Carex lyngbyei, the Lyngbye's sedge is a member of the sedge family (Cyperaceae). The Icelandic name of this species is Gulstör.
There is only one other common sedge on Iceland that compares in height, being the Bottle sedge (Carex rostrata), be it that the "juncea" subspecies/variety of the Common Sedge (Carex nigra) is at least as tall. The latter is though not very common on Iceland.
C. lyngbyei and rostrata are easily differentiated: Lyngbye's sedge has drooping 2-stigma female spikes whereas the Bottle sedge has stiff 3-stigma upright female spikes. Both species grow abundantly in lakes, ponds and marshes. However there are some gradual differences in habitats: the bottlesedge is seen more often along pools where the Lyngbye's sedge is found more often in marshy grasslands. The Lyngbye's sedge grows in lowland regions. Carex lyngbyei is an American species, naturally growing on Iceland but missing in mainland Europe. There is a close relative species - by some regarded to be a hybrid of lynbyei x subspathacea being the Ramensk's sedge (Carex ramenskii - Icelandic name: Marstör).