There are over 3000 species in the Solanaceae (Nightshade family). This family has many food crops, including eggplants, tomatoes, and peppers. However, many species are toxic. The potato is one of the most important crops. It has been grown by people for at least 7,000 years, starting in Peru. The part we eat is an underground stem called a tuber.
- "Solanum tuberosum". Encyclopedia of Life, available from: http://eol.org/pages/482935/details
- Classification for Kingdom Plantae Down to Genus Domingoa Schltr. USDA Plants Database, available from: http://plants.usda.gov/java/ClassificationServlet?source=display&classid=Solanaceae
- Solanaceae Source from the Natural History Museum in London http://www.nhm.ac.uk/research-curation/research/projects/solanaceaesource/solanaceae/classification.jsp
- “Solanaceae.” Wikipedia, The Free Encyclopedia. Available from: http://en.wikipedia.org/wiki/Solanaceae
- “Solanum tuberosum.” Wikipedia, The Free Encyclopedia. Available from: http://en.wikipedia.org/wiki/Solanum_tuberosum
Actually, if you look worldwide, there are over 3000 species in the Solanaceae (Nightshade family). See http://www.nhm.ac.uk/research-curation/research/projects/solanaceaesource/solanaceae/classification.jsp (the Solanaceae Source from the Natural History Museum in London).