See the context of this sign.

Chihuahuan Desert

Despite a tendency to spiny plants, barren ground, and a
variety of reptiles, each desert is distinctive. To recognize
the Chihuahuan, shift focus from the broad horizon to the
"indicator plants" that characterize this particular landscape.

The agave lechuguilla grows only in the Chihuahuan
Desert. Bladed like a cluster of daggers, lechuguilla thrives in
gravelly soil with less than ten inches of precipitation a year.
Look for this needle-tipped plant along the short trail.

From here the Chihuahuan Desert extends south for
300 miles into central Mexico. Most of this desert lies
in a high plateau between mountain ranges.

Don't miss the rest of our virtual tour of Big Bend National Park in 1083 images.