Hypericum humifusum
- Photograph of Trailing St John’s Wort and a description of the plant.
- http://www.plant-identification.co.uk/skye/guttiferae/hypericum-humifusum.html

Hypericum pulchrum
- Several photographs of leaves and flowers of slender St John’s Wort and its description.
- http://www.plant-identification.co.uk/skye/guttiferae/hypericum-pulchrum.htm

Hypericum androsaemum
- Several photographs of Tutsan and some identifying features of the plant.
- http://www.plant-identification.co.uk/skye/guttiferae/hypericum-androsaemum.html

Hypericum tetrapterum
- Several photographs of Square-stemmed St John’s Wort and some identifying features of the plant.
- http://www.plant-identification.co.uk/skye/guttiferae/hypericum-tetrapterum.html

Hypericum perforatum
- Photo and profile of common St. Johnswort, with particular focus on its status as a noxious weed in parts of the U.S.
- http://plants.usda.gov/java/profile?symbol=HYPE

Hypericum crux-andreae
- St. Peterswort.
- http://plants.usda.gov/java/profile?symbol=HYCR3

Hypericum hypericoides ssp. hypericoides
- St. Andrew's Cross.
- http://plants.usda.gov/java/profile?symbol=HYHYH

Hypericum calycinum
- image
- http://www.botany.hawaii.edu/faculty/carr/images/hyp_cal.jpg