Eyes on a Parasite

Eyebright, Euphrasia spp.

A pretty, summer to autumn flowering plant of calcareous grasslands and sand dunes, Eyebright has long confused taxonomists (1). The similarity of the species and their tendancy to hybridise with each other means that the 20+ species present in Ireland and Britain as grouped together as Euphrasia officinalis agg.. Considered scarce around Ireland (2), the flowers are basically white but may have purple veins, yellow patches or may even be pink (3). Eyebrights are hemiparasites of grasses and other plants. They produce haustoria at their root tips that burrow into the roots of the host and extract nutrients (4). Plants are capable of surviving without a host, however growth is reduced in such individuals (5).

References:

1. Silverside, 1991. Watsonia 18 pp. 343-350
2. Sterry, 2004. Collins Complete Guide to Irish Wildlife p. 242
3. Phillips, 1977. Wildflowers of Britain p. 92
4. Yeo, 1961. Watsonia 5 pp. 11-22
5. Yeo, 1964. Watsonia 6 pp. 1-24