Luzula sudetica; The Sudetan Wood-rush is very similar to the Heath Wood-rush (Luzula multiflora). The most striking difference concerns the inflorescences on each stem. In the Sudetan Wood-rush this is generally limited to a few strongly contracted bunch of flowers usually on very small stalks so they often appear as one bunch. However, sometimes the stalks are longer. The Heath Wood-rush has several bunches of flowers on each flowering stem. Each has a rather long stalk so they appear as separate bunches. The flowers of the Sudetan are darker (blackish vs brown). Other color differences: The Sudetan Wood Rush has reddish top parts of stems and sometimes whole plants are red coloured. Having said all this I think it is quite tricky identifying these species by the colors as the Heath Wood-rush at times can also be red tainted. A more telling difference concerns the morphology of the single flowers: like rushes heath-rushes have 6 small flower leaves (perianth leaves) arranged in three inner and three outer perianth leaves. In the Sudetan Wood-rush the outer leaves are clearly larger then the inner while in the Heath Wood-rush they are of equal length (requires magnifying glass for most observers).
The Sudetan Wood-rush (Luzula sudetica) is a member of the rush family (Juncaceae). The Icelandic name of this species is Dökkhæra.