As the road ascends the hill, notice the conspicuous desert plant growing along the hillsides. One of the most common questions answered by park rangers at Big Bend is, "What is the name of that plant with tall, thin, vertical branches that we see everywhere in the park?". This plant is called an ocotillo (pronounced o-ko-tee-yo), and it has developed an unusual mechanism to conserve water in this dry environment. Most of the year this unique plant appears to be nothing more than a cluster of gray thorny stalks that many people mistake for a cactus. With adequate rain, ocotillo will produce numerous bright green leaves that allow for a "spurt" of growth. When the soil dries, the leaves drop off to conserve moisture. Although the plant appears dormant, it can still photosynthesize through the green stripes on its bark.