Cylindropuntia munzii

Armor. Spines protect the plant from hungry and thirsty animals (including humans). Animals need water and nutrients to stay alive. Plants are a great source of water and nutrients for animals, but plants need to hold onto their own water and nutrients! Armor is an adaptation to protect the plant from hungry animals. The spines also provide shade to this desert plant. 

Succulence. These stems are thick because they are full of water. Succulent plants often have squishy leaves or stems because the organ is filled with liquid!  Succulence is when a plant stores water in its leaves or stems. This Cholla stores water in its stems.  When it is very dry in the plant's environment, this plant can use its stored water to help it stay alive. Succulence is an adaptation to help the plant survive in hot and dry environments.

No Leaves. Leaves take energy to keep alive. Leaves are covered in tiny pores called stomas. Stomas release water into the environment when they open. Plants living in places with very little water need to save as much water as they can, and this adaptation can help with that. Instead of making leaves to photosynthesize, this plant uses its stem for photosynthesis. The stomas are on the stem surface. Having no leaves is an adaptation to help the plant survive in hot and dry environments. 

Vertical Branches. The vertical branches help the plant stay cool. Overheating is dangerous for people, and it is dangerous for plants too!  Vertical branches are an adaptation to minimize the parts of the plant facing the sun during the hottest part of the day. This shade helps the plant keep its water longer. Vertical branches are an adaptation to help the plant survive in hot and dry environments. 

Waxy Surfaces. All leaves have a cuticle that protects the leaf and helps to keep water inside. Some stems also have a waxy covering on the outside. Some plants have adapted an especially thick waxy cuticle. When the cuticle is thick, the plant keeps even more water inside! Waxy cuticles are an adaptation to help the plant survive in hot and dry environments.

Pale Stems. Pale stems reflect more sunlight than dark stems. Pale stems absorb less heat than dark stems. This prevents overheating! Overheating is dangerous for people, and it is dangerous for plants too! Pale stems are an adaptation to help the plant survive in hot and dry environments. 

Which color do you think best matches the outside of the stems of this plant? Which color best matches the inside of the stems?