West Highland Flora

Common Sedge


Carex nigra

 

Carex nigra

Photo Carl Farmer
31 May 2003 Storr, Skye
Male (top) spike 20 mm
Lower female spike 18 mm

Common in wet ground at all altitudes, especially on moorland, but occurs in a wide variety of soil types.

Stems c 10-40 cm tall.  Female spikes c 10-20 mm long.  Fruit c 2.5-3 mm.

ID: Female spikes strikingly black in flower, giving a black and green chequered effect when in fruit.  Lowest bract nearly as long as, or often longer than, inflorescence.  Stem three-cornered but edges rounded.  Only likely to be confused with Stiff Sedge, but that has lowest bract well short of inflorescence and stem edges sharply angled.  Leaves of Common Sedge have stomata all or mostly on the topside, those of Stiff Sedge have them all on the underside.  This can be seen with a lens in the field.  Told from Glaucous Sedge in flower by having only 2 stigmas, and in fruit by the fruit being narrow in side view, very two-sided, with one side more or less flat and the other convex.  Also the glumes of Glaucous Sedge are not jet black as in this species.

Other features: Many of the stems have two male spikes, the second usually much smaller than the main one, alongside it and hard to spot.  Female spikes normally 2-3, unstalked or the lower ones with short stalks.  Leaves often glaucous, sometimes on one side only.  Often found with Marsh Horsetail dominating a wet patch of ground.

 

Carex nigra

Photo Carl Farmer
5 May 2002 Scorrybreac, Skye

  Carex nigra

Photo Carl Farmer
14 May 2003 Skeabost, Skye

  Picture above shows second small male
 spike at base of large one

 

 

 

 

Photo Carl Farmer
14 May 2003 Skeabost, Skye

 

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