Cacti are amazing organisms. They live in the most challenging environments and continue to survive. The Cactus family diverged from other related plants about 35 million years ago. Interestingly, most species are from the New World of the Americas. Asia and Africa's Mistletoe Cactus (Rhipsalis baccifera) is the one exception.

Oldest Plants

You may think that cacti could live very long under desert-like conditions. Indeed, drought is a regular occurrence in many of their habitats. Trees are among the oldest living plants, with some colonies existing for thousands of years. The oldest tree resides in the White Mountains of California, estimated at 5,062 years old.

Cacti are a different story. Scientists believe that most species live about 20 years. However, there are some hardier members of this family. Saguaros can make it up to 200 years. The Fishhook Barrel Cactus (Ferocactus wislizenii) also has a long lifespan of up to 100 years. The Totem Pole Cactus is another species that is equally as long-lived. You may wonder how they can live in such dry places.

Cacti Adaptations

Living in a dry area creates various obstacles. Minimizing water loss is crucial. Cacti possess distinct features, being part of the succulent plant group. Instead of depending on environmental conditions for hydration all year, they retain water in their fleshy pads and trunks.

Cacti slow evaporation with a thick waxy outer layer that minimizes water loss. Plants exchange moisture with the air around them. They take in carbon dioxide and give off oxygen through openings in their leaves called stomata. Usually, it occurs during the day when photosynthesis is happening. Cacti conduct gas exchange at night to reduce evaporation and conserve water.

Cacti are often associated with their needles or spines, reducing moisture loss and protecting them from animals. These adaptations provide an evolutionary advantage for cacti survival.

Cacti struggle in wet conditions due to their shallow roots, which absorb water quickly but lack anchoring, making them prone to rot.

Final Thoughts

Cacti are excellent examples of plants that have made the best of their fate. They have adapted to live where other species would struggle, even the largest trees. Old Man Cactus is a lot tougher than anyone would guess.