FLORA OF ICELAND elements: Euphrasia stricta, Drug Eyebright, Kirtilaugnfró

Euphrasia stricta; The drug eyebright is a far more rare species than the cold eybright. It is found on a few localities around Iceland. It grows in rather same vegetation types as the cold eybright, however it is often found on thermal soils - but not always. Positively identifying this species from the cold eybright is difficult. There are some relative traits, like the drug eyebright is larger, has more (longer) sidebranches and has darker purple streaks in the flowers. However there is a large overlap in these traits between the species. A more devisive trait concerns the hairs on the calyx of the flowers. Those on the cold eyebright are normal, whereas they are glandular on the drug eyebright (see photo). Another complication in identifying them is that Euphrasia's are known to hybridize frequently. I am not certain how easily these species hybridize, though.
Members of the Euphrasia's are known to parasite on the roots of other plants, especially grasses.
It is a member of the broomrape family (Orobranchaceae) but in the past it was considered to be a member of the figwort family (Scrophulariaceae). The Icelandic name of this species is Kirtilaugnfró.