How Many Species of Cacti Are There? (2026 Data)

By Emma Johnson · January 24, 2026

How Many Species of Cacti Are There?

There are approximately 1,750 recognized species of cacti, distributed across about 127 genera. These numbers are dynamic due to ongoing taxonomic research, DNA analysis, and the discovery of new species, particularly in remote regions of Mexico and South America.

Understanding Cactus Diversity

Cacti belong to the plant family Cactaceae, one of the most distinctive families in the plant kingdom due to their specialized adaptations to arid environments. Their diversity spans a wide range of forms—from tiny globular cacti to towering columnar species and sprawling epiphytic types.

Key Characteristics of Cacti

Presence of areoles—specialized structures from which spines, flowers, and branches grow
Thick, fleshy stems capable of storing water
Reduced or absent leaves (in most species) to minimize water loss
Widespread adaptation to hot, dry climates, though some grow in rainforests

Classification and Taxonomy of Cacti

The classification of cacti has evolved significantly with advances in molecular phylogenetics. Traditionally grouped by morphology, modern systems rely on genetic data to define relationships among genera and species.

Major Subfamilies of Cactaceae

Pereskioideae: Leafy cacti retaining primitive traits
Opuntioideae: Includes prickly pears and chollas, known for glochids
Maihuenioideae: A small subfamily with only one genus (Maihuenia)
Cactoideae: The largest subfamily, containing most iconic desert cacti

Subfamily	Number of Genera	Number of Species	Notable Examples
Pereskioideae	2	17	Pereskia aculeata
Opuntioideae	14	~300	Opuntia ficus-indica, Cylindropuntia imbricata
Maihuenioideae	1	2	Maihuenia poeppigii
Cactoideae	110	~1,400	Saguaro (Carnegiea gigantea), Echinocactus grusonii

Table data source:1, 2

The data shows that Cactoideae dominates cactus diversity, accounting for nearly 80% of all species. Meanwhile, Opuntioideae contains fewer species but is highly morphologically diverse. Recent DNA studies continue to refine these groupings, occasionally leading to reclassification.

Geographic Distribution of Cactus Species

Cacti are native almost exclusively to the Americas, ranging from Canada to Patagonia. The greatest concentration occurs in Mexico and the southwestern United States, followed by the deserts and dry forests of eastern Brazil and the Andes.

Hotspots of Cactus Biodiversity

Mexico: Home to over 600 endemic species, especially in the Chihuahuan Desert
Central America: Rich in epiphytic cacti like Epiphyllum and Schlumbergera
South America: Diverse populations in Argentina, Bolivia, and Paraguay
Caribbean Islands: Unique island endemics, often critically endangered

Challenges in Counting Cactus Species

The exact number of cactus species fluctuates due to several factors:

New discoveries: Botanists describe 10–20 new species annually, mainly in underexplored areas
Taxonomic revisions: Genetic studies often merge or split species
Hybridization: Natural hybrids blur species boundaries, especially in Opuntia
Conservation status: Over 30% of cacti are threatened, complicating field surveys

Frequently Asked Questions About Cactus Species

Are all cacti desert plants?

No, while most cacti thrive in arid environments, some species—like Epiphyllum and Rhipsalis baccifera—grow in tropical rainforests as epiphytes on trees. These have reduced spines and rely on humid air for moisture.

What is the largest cactus species?

The Saguaro (Carnegiea gigantea) is the tallest, reaching up to 40 feet (12 meters). It grows slowly, taking 75 years to develop its first arm, and can live over 150 years.

How many cactus species are endangered?

According to the IUCN Red List, more than 31% of assessed cactus species are threatened with extinction, primarily due to habitat loss and illegal collection. This makes cacti one of the most threatened plant groups.

Can cacti be found outside the Americas?

Naturally, cacti are only native to the Americas. However, some species like Opuntia stricta have become invasive in regions such as Australia and South Africa due to human introduction.

How do scientists identify new cactus species?

Botanists use a combination of field observation, morphological analysis (spine pattern, flower structure), and DNA sequencing. New species are formally described in scientific journals with type specimens deposited in herbaria.