Cactaceae
Cactaceae Juss. comprises approximately 125–130 genera and 1,750–1,900 species, nearly all of which are native to the Americas, with the exception of Rhipsalis baccifera, which also occurs naturally in parts of Africa and Asia. Molecular phylogenetic studies have clarified relationships among major subfamilies, including Pereskioideae, Opuntioideae, Maihuenioideae, and Cactoideae, confirming the monophyly of the family. Cactaceae is distinguished by its succulent stems, specialized areoles, reduced leaves, and remarkable adaptations to arid environments.
Key characteristics
- Perennial succulent herbs, shrubs, climbers, or tree-like plants
- Stems fleshy, green, ribbed or tuberculate, and photosynthetic
- Leaves absent or reduced to spines
- Areoles present, producing spines, flowers, and branches
- Flowers solitary, usually large and bisexual
- Inferior ovary
- Fruit a fleshy berry containing numerous seeds
Distribution
Cactaceae is native primarily to North, Central, and South America, extending from southern Canada to Patagonia. The family reaches its greatest diversity in Mexico, the Andes, Brazil, Argentina, Bolivia, and arid regions of the southwestern United States. Members inhabit deserts, semi-deserts, dry forests, rocky outcrops, coastal dunes, savannas, and tropical rainforests, where numerous epiphytic species occur. Many cacti have been introduced and cultivated worldwide in arid and subtropical regions. Cactaceae is not indigenous to Pakistan. Numerous species are cultivated throughout Capital Territory, as ornamental plants in home gardens, botanical gardens, nurseries, parks, and greenhouses. Species of Opuntia have become locally naturalized in some dry areas of, while many other genera are maintained exclusively under cultivation.