Opuntia is the largest group of Cacti with over 360 species ranging from Canada to Chile and Argentina. This group also includes several edible kinds. These plants are commonly known as Bunny Ears, Cholla, Prickly Pear, Barbary Fig, Tuna and Indian Fig.

Opuntia is usually separated into two groups.
The first group is Platyopuntia;
those belonging to this group have round flattened joints, called pads. They are commonly known as Prickly Pears because they produce the spiny, usually edible, fruits. Some are grown for their edible pads called nopales or nopalitos. The spines of these pads must be singed off before they can be prepared for eating.
The second group is Cylindropuntia;
those belonging to this group have long, cylindrical joints and are commonly called Chollas. The sizes of Opuntias vary. They can be just a few inches and spreading, or grow 100 feet high and tree-like. Most kinds of these plants are covered with sharp, barbed spines that are difficult to remove without lacerating the skin.
An interesting characteristic of these plants is the glochids. These are small, barbed spines produced at the base of the large spines. They can be very irritating if not handled carefully. The flowers, which are borne from spring to fall, are shaped like cups or saucers. They are produced singly on the upper parts of the joints. They have many petals and they average 3 inches in diameter. They are usually yellow but can come in purple, orange or red.

O. lindheimeri is a pretty variety that grows up to 4 feet high with a spread of up to 10 feet. This spreading plant grows only two or three pads high. The pads are covered with cushions of golden brown glochids. In the summer, bright orange or dark red flowers are produced at the edges of the pads; these are followed by purple fruits.

O. tunicata is an interesting plant that grows up to 3 feet high with a spread of 6 feet. Young plants have few spines, but older plants are densely covered in barbed spines that have a silvery radiance in bright light. In the summer, gold to pink flowers and greenish-yellow fruits decorate this plant.

O. microdasys is a spineless variety, though it is covered with tufts of irritating, barbed glochids. The flowers of this plant and its varieties are ordinarily yellow.

Cactus Properties Used by the Aztec's

As a Tonic for the Heart,  Chest Angina,  Heart Murmur,  Arithmia,  Tissue Redness,  Mental Depression,  Promotes Arterial Pressure thereby acting as a diuretic and increasing the amount of urine