Caltha palustris
- Two photographs of the Marsh Marigold and information on features helping in its identification.
- http://www.plant-identification.co.uk/skye/ranunculaceae/caltha-palustris.htm

Caltha leptosepala spp. howellii (Marshmarigold)
- Image and brief description of this plant.
- http://www.cwnp.org/photopgs/cdoc/caleptosepala.html

Caltha palustris - Marsh Marigold
- Image, description, and toxicity.
- http://www.ces.ncsu.edu/depts/hort/consumer/poison/Calthpa.htm

Caltha leptosepala
- image
- http://www.botany.hawaii.edu/faculty/carr/images/cal_lep.jpg