Giant Prickly Pear

The small island of Santa Fé has one of the several endemic subspecies of Galápagos Giant Prickly Pear. There are six full species divided into fourteen different varieties. The Santa Fé version is Opuntia echios barringtonensis. The various subspecies are believed to be strong examples of adaptive radiation, in that they have adapted in size and sharpness of spine to cope with Giant Tortoises and Land Iguanas, or the lack of them.
The Santa Fé subspecies has the largest girth in the islands - up to 2.60 m/8’ 6”, and has the largest fruits.
The plant starts life as a series of pads growing one on top of the other, then, when it reaches a certain height, starts to branch out. It is believed that the stiff, sharp spines serve to protect the plant in its early stages.

The thick pads are not leaves, but are in fact the stem of the plant. The spines are the leaves.

Opuntias do not become woody, and both the 'trunk' and the pads consist of many layers of fibrous, honeycomb material.

At a certain stage in its slow development, the 'trunk' becomes brown, smooth and shiny. In this photo, you can just about make out the horizontal lines which mark the separate pads, as were, but in some older individuals, this can be difficult to see.

Both Tortoises and Land Iguanas enjoy the pads and fruit of the opuntias, and land iguanas are also said to enjoy the yellow flowers, and to investigate anything yellow. Doves and Mockingbirds also eat the flowers, and the Cactus Finches depend on the flowers, fruits, seed and on water from the pads.