Cactus

Like other succulents, cactuses (or cacti, but not 'cactus' in the plural) are well-adapted to life with little precipitation. Their leaves have degenerated into needles, which in addition to allowing less water to evaporate than regular leaves, also defend the cactus against water-seeking animals. Their photosynthesis is carried out by their enlarged stems[?], which also store water.

Cactuses come in many varieties in a wide range of shapes and sizes. Some cactuses produce beautiful flowers; others grow to enormous heights. Many cactus species are nightblooming, as they are pollinated by nocturnal insects or small animals.

A number of cactus species are cultivated for use as houseplants, as well as for ornamental gardens. They often form part of xerophilic (dry) gardens in arid regions. Some cacti bear edible fruit.

A few varieties of cactus:

• Barrel cactus[?]
• Apple cactus
• Opuntia[?]
• Old man cactus[?]
• Prickly pear
• Saguaro