Cactaceae -- comments
Comments: Great group, many commonly cultivated members including: Cereus, Epiphyllum (Orchid Cactus), Mammillaria, Opuntia (Prickly Pear, edible), Rhipsalis, and Schlumbergera (Christmas Cactus). CAM photosynthesis extremely common in members. The family is typically divided into subfamilies based on various leaf and stem characters.
The Cactaceae is a New World family, but there is one disjunct genus, Rhipsalis, that is found on the west coast of Africa. How do you think it got there?
This could be evidence that this family as a whole:
1) evolved before the Gondwana continent (Africa, South America, India, Antarctica) had completely split and this family died out except in South America and Africa
2) evolved in South America and was later dispersed to Africa across the Atlantic
How could you use taxonomy or phylogenetics to try and answer this question?