There are over twenty Euphrasia species
Eyebrights are a semi-parasitic flower and the species are all so similar that it is not recommended that amateurs like me attempt to differentiate between them. They tend to grow in short grass and are common near me on chalk downland.
Depending on how exposed the site is, I have seen the plants from about 2cm high, up to about 15cm. They sometimes have a red tinge on the stems and leaves. The tiny white flowers are a few millimetres across and have a yellow centre and purple stripes. They flower June to September.
The most common species is Common eyebright, Euphrasia nemorosa. This species is very common on the South Downs in Sussex
Eyebrights grow in chalk grassland