FLORA OF ICELAND elements: Carex macloviana, Thick-head Sedge, Kollstör

Carex macloviana; The Thick-head Sedge has a cespitose base of leaf-rosettes with green leaves and dead leaves from previous years. The culms grow up to 30cm on Iceland but can grow taller in other countries.
   The leaves are about 3mm wide, rough-edged. The stems are leaf-less; furrowed and triangular especially near the top of the stem.
  The spikes are closely contracted at the top. There are small dark-colored scaly bracts at the bottom of the spikes. The male flowers are at the bottom of the spikes, disappearing quickly. The female flowers have two stigma's. The fruits are characterized by long-pointed utricles.
  It is quite rare, generally found in grass- and heathlands in northern and central regions of Iceland.
  The Thick-head Sedge is a member of the sedge family (Cyperaceae). The Icelandic name of this species is Kollstör.

The species Carex maritima, C. norvegica and C. macloviana closely resemble each other. This is how you can tell them apart:
   Carex maritima is the only of the three species that have the male flowers in the top part of the spikes. Remnants of these stay long visible after flowering. They are a bit smaller (maximally 20cm; 30cm for both other species). Quite conspicuous are the bent culms where they are straight vertical in the other two species. In young examples / early spring this may not be visible yet.
   Carex norvegica is the only species (of these three) that has a leaf-like bract under the inflorescense. The utricles of C. norvegica are short, in C. macloviana they are long
   On one location Carex caryophyllea has been found on Iceland (therefore extremely rare). It also has the spikes concentrated at the top of the culms. It differs fundamentally in that the top spike has (nearly) only male flowers. The utricles are hairy. As such they resemble Carex pilulifera.