What are arid plants?
Desert biomes are characterized by experiencing low rainfall and extreme temperature fluctuations. As a result, desert environments are not able to support as much vegetation as other ecosystems. Despite this, deserts are home to a diverse variety of plants that have adapted to survive in these harsh conditions. Euphorbias, cacti, and asclepiads are just a few examples of the types of plants that can be found in desert regions.
What makes them special?
Desert flora have adapted to survive for long periods without rain. Native to deserts in the Americas, cacti are types of succulents characterized by their thick stems that store water. These succulents typically absorb water through their wide yet shallow root systems, which efficiently take up water right after it rains. To prevent this water from evaporating, cacti have developed minimal leaves, sharp spines, and waxy coatings on their stems. Cacti, along with most other desert plants, also utilize CAM photosynthesis, meaning that they only open their pores to take in carbon dioxide at night. This adaptation helps the plants avoid drying out during the day.
Adapting to the hot and dry desert conditions manifests differently in other plant families. While they may appear similar to cacti at first, succulent euphorbias have a few characteristics that set them apart from their lookalikes. For instance, the spines of cacti are different from the stipular spines of euphorbias. Euphorbs are also able to deter herbivores from eating them by secreting a milky, poisonous sap.
Another interesting adaptation many desert plants have evolved is going dormant during dry spells. These plants hold off on growing any further until their conditions are more favorable. Once the rain begins to fall, the plants will quickly grow and complete their life cycle so that they’re able to reproduce. This causes otherwise sparsely vegetated deserts to suddenly bloom with colorful flowers after heavy rainfall in the phenomenon known as a superbloom.
Fun facts
One particularly dangerous desert plant growing in the Conservatory is the jumping cholla. This cactus plant typically grows in regions of the southwestern United States and northwestern Mexico. Jumping chollas get their name from their stems which easily detach from the plant if their spines brush against anything. These cacti don’t just have your typical spines either. Jumping chollas have barbed spines, which would make them especially difficult and painful to remove from your skin. These spines help deter herbivores and also allow their stems to latch onto animals, helping the plant to disperse over short distances.