Empetraceae
- Botanical characteristics of this family of small shrubs with illustrations of Empetrum nigrum.
- http://delta-intkey.com/angio/www/empetrac.htm

Empetrum hermaphroditum
- Photographs of Mountain Crowberry and some identifying features.
- http://www.plant-identification.co.uk/skye/empetraceae/empetrum-hermaphroditum.htm

Empetrum nigrum
- Information and several photographs of Common Crowberry including one in its natural habitat on the Isle of Skye.
- http://www.plant-identification.co.uk/skye/empetraceae/empetrum-nigrum.htm