The Cacti of South America

Peru is one of the principal centres of cactus diversity in South America. A classic synthesis of the family in the country recognised 43 genera and nearly 250 species, including 199 endemic taxa in 32 genera and six endemic genera, while more recent national references cite 42 genera, 270 species and seven endemic genera, showing both the exceptional richness of the country and the fact that cactus taxonomy and discovery in Peru remain active fields of research.

This diversity is not only taxonomically remarkable, but also relevant from a conservation perspective. A global assessment showed that cacti are among the most threatened taxonomic groups evaluated to date, with 31% of assessed species classified as threatened with extinction. In practical terms, this means that a specialised route focused on cactus observation and photography is not merely an aesthetic experience: it can also be framed as a conservation-aware journey through one of the most vulnerable plant groups in the world’s drylands.

From a biogeographical perspective, the western slopes of the Peruvian Andes are especially important because cactus communities are not randomly distributed. Their composition is structured by aridity, altitude, maritime humidity and regional climatic regimes. A phytosociological analysis across the western Andes of Peru showed that cactus communities are concentrated in the coastal desert lomas and the basal Andean belts, and that southern Peruvian communities belong to distinct biogeographical and bioclimatic settings. This is precisely why a route in southern Peru is so compelling: within a relatively compact itinerary, it is possible to move across fog-fed coastal desert, inter-Andean dry valleys and volcanic highland landscapes while still remaining within a coherent, cactus-centred programme.

For a first cactus itinerary in Peru, Arequipa is arguably the strongest region to prioritise. A departmental catalogue documented 56 non-cultivated taxa, with especially high representation of Cumulopuntia (11 spp.), Corryocactus (7 spp.) and Loxanthocereus (6 spp.), and reported 21 endemic taxa in the department. This means that Arequipa combines richness, endemism and genus-level variety better than most regions that are also realistically accessible for a well-operated tour.

This itinerary links three complementary sectors of southern Peru. First, Atiquipa, where the route enters the lomas system: a fog-dependent oasis ecosystem embedded in one of the driest regions of the continent. Second, the Cháparra Valley, one of the best-documented cactus valleys in southern Peru in terms of endemism. Third, Andagua and the Valley of the Volcanoes, where cactus observation is set within one of the most distinctive volcanic landscapes in the Peruvian Andes. Together, these localities create a route that is both botanically rich and visually dramatic.

The Lomas de Atiquipa are especially important because they are not only scenic, but also ecologically exceptional. Official tourism information identifies them as the largest and most diverse coastal lomas in Peru, covering 19,028.02 ha. The cactus flora of Atiquipa documented 15 genera and 20 species, of which 13 are endemic to Peru and eight to Arequipa; within the lomas zone itself, the highest cactus diversity was recorded between 600 and 1,200 m, and the lomas sector concentrates 16 species. In other words, Atiquipa is one of the few places where a visitor can experience the visual drama of a fog oasis while simultaneously working with a highly diverse cactus assemblage.

The Cháparra Valley provides a different but equally strong cactus experience. A dedicated inventory reported 23 taxa, including 18 endemics to Peru and two exclusive to Arequipa, across a broad environmental gradient from coastal lowlands to higher dry valleys. This locality is particularly attractive because it adds not only species richness, but also a strong endemism component and a clearer view of cactus distribution across an arid valley system.

The Valley of the Volcanoes in Andagua adds a third dimension to the trip: geological spectacle. The valley is a distinctive landscape with 36 miniature volcanic cones, lava flows and three lagoons, as well as 269 plant species and 115 bird species, while UNESCO highlights the broader Colca y Volcanes de Andagua UNESCO Global Geopark as a place where volcanic landforms, deep canyon systems and living local cultures intersect. The botanical interest of the valley has been reinforced by the recent description of Corryocactus volcanicus, a new species from this very landscape. This combination of scenery, geological identity and ongoing botanical discovery gives Andagua exceptional value for a high-end natural history route.

This route is also particularly strong for nature photography. The visual transitions are striking: fog-fed green patches against hyper-arid slopes in Atiquipa, sculptural cactus stands in dry valleys in Cháparra, and volcanic cones, lava fields, high Andean skies and broad valley views in Andagua. For photographers, this offers a rare combination of macro opportunities, cactus-in-habitat images, wide-angle landscape compositions and documentary natural history scenes within a single itinerary. This is not a flower-only tour; rather, it is a route for photographing cactus diversity, structure, landscape context and ecological setting.

This itinerary connects biodiversity with human landscape history. Coastal lomas have been described as fog oases and centres of both biodiversity and past human activity, while the Andagua sector lies within a geopark where geodiversity, traditional practices and community-based tourism are explicitly linked. It is therefore a journey through the ecology, geology and cultural history of southern Peru’s drylands.

We’ll fly directly from Lima in Peru to Cordoba in Argentina where we’ll explore an entirely different cactoid flora. Over seventy species of Cacti clothe the mind-boggling landscapes of Northwestern Argentina, ranging from three hundred year old Trichocereus pasacana cacti growing 3m tall, to the improbably tiny Blossfeldia liliputana. The extraordinary growth forms of these cacti are many and varied and so are the often magnificent blooms. Tall white-hairy Cleistocactus hyalacanthus has stunning tubular pink flowers whilst the impressive orange-yellow blooms of Lobivia aurea dwarf the plant itself. We’ll see Saguaro-like Trichocereus terscheckii, and exquisite Parodia mesembrina, the globular ball of spines overtopped by brilliant yellow blooms. Soehrensia formosa is a study of brilliance, its scarlet blooms obvious from afar, and we’ll see the extraordinary Rebutia senilis, a beauty whose squat little body is garlanded with magnificent blooms of red, yellow or orange.

The Quebrada de Humahuaca, an ancient Inca Road that connects Bolivia and Argentina, takes us through some of the most spectacular scenery in South America. 5000m high volcanoes tower over us as we explore the biologically diverse Yungas Cloudforest en route to the unique high-altitude deserts of the Altiplano. Andean, Chilean and Puna Flamingos glean shrimps among Giant Coots and Giant Grebes as we watch herds of Vicuña graze with Darwin’s Rheas in this sublime wilderness. The magnificent Andean Condor will be seen on an almost daily basis, and other marvellous birds include Blue-crowned Trogon and some beautiful Hummingbirds such as the colourful Red-tailed Comet, Blue-capped Puffleg and the magnificent Giant Hummingbird. Hieroglyph engraved menhirs sit among dry Chaco forest where the arching columns of Echinopsis grandiflora serve as a vase for the red flowers and Rebutia jujuyana isencircled with jubilant orange blooms. We’llfind plenty of evidence of the Inca’s Empire of the Sun and other cultural wonders include picturesque Purmamarca, nestling at the foot of the Mountain of Seven Colours, its church adorned with Cactus woodwork!