Rain Gauge

A leaf is a leaf is a … rain gauge? Yup. Sort of. Brittlebush leaves act like Ma Nature’s precip monitor. The drier it is, the smaller and whiter the leaves it produces. If the soil dries up too much the leaves drop off altogether.

The we’ve-got-enough-water leaves are dark green, almost hairless. Turn up the heat and turn off the tap and that changes quickly — the next leaves to appear will be greyer and covered by white hairs. Those two factors keep the leaves from overheating by reflecting the sunlight. The tiny hairs also trap moisture.

I took the leaf shots this morning just as the rain started — the wet leaves really show the colour contrast.


Brittlebush is one of the most common plants on the Sonoran Desert. It grows in a half moon shape, like an upsidedown bowl. That shape and the profusion of eye-popping yellow flowers make it easily recognizable.

The image below shows what happens to a single bush when it moves into town and onto a lot where the owner waters plants. Wow. 🙂


Brittlebush   Encelia farninosa
Chuparosa    Justicia californica (aka Beloperone californica)
Palo verde   Parkinsonia aculeata