The cactus trees of the Galapagos are the world's biggest cactus species. They are true cacti in the family
Cactaceae, comprised several thousand species. Many Galapagos cacti are endemic, including several species of
Opuntia, the genus to which the cactus tree belongs. Cacti are different from most other plants because they have
a photosynthesis system that is more efficient. Cacti do not have leaves and photosynthesis occurs in the green
stems. The spines protect the soft, water-filled stems from hungry, thirsty animals, and if very dense, the spines
shade the stem from the heat of the sun.
Click below to see the photos and information on cacti:
The tree-like cactus (Opuntia echios) occurs on most islands, but reach their greatest size on Santa Fé Island, where this photo was taken.
They may grow to 35 feet high. Similar tree species occur on other islands, but the biggest recorded individual
was on Santa Fé. It fell over during the rainy period of the 1997-98 El Niño.
This picture shows the sequence of flower development of Opuntia. An area from which spines are growing out
swells up and develops a globular shape. The center fills (lower right) and then a flower bud forms. Opuntia
flowers are bright yellow to orange in full-bloom. They produce lots of pollen and nectar and provide food for a
variety of animals including the cactus finch, which depends on the cactus for sustenance. This picture was taken
on Rabida Island, on the trail behind Red Beach.