Ocotillo or Fouquieria splendens

The new budding stems on the Ocotillo plant (Fouquieria splendens) are red for several biological and ecological reasons:
Protection from UV Radiation:
Young stems are more sensitive to sunlight. The red pigmentation often comes from anthocyanins, which can protect the plant from harmful UV rays by acting as a natural sunscreen.

Deterrent to Herbivores:
The bright red color may serve as a visual warning to herbivores that the new growth is tough, potentially unpalatable, or chemically protected.

Temperature Regulation:
Red pigments can help regulate the absorption of heat. This is especially beneficial in the Ocotillo's native desert environment, where temperatures can fluctuate dramatically.

Photosynthesis Support:
While new stems are still developing their full complement of chlorophyll (green pigment), anthocyanins can help by absorbing additional wavelengths of light, aiding in energy capture until the stem turns green.

This red coloration usually fades as the stems mature and develop a more chlorophyll-rich, green hue, making them more efficient for photosynthesis.