Digitaria californica

Arizona Cottontop

Field view of Digitaria californica (in front of the cactus), common name Arizona Cottontop.

The spike-like inflorescence is soft and elongate. The spikelets show through as dark dots.

Digitaria californica is usually knee high to below shoulder high. Here are parts of the robust stems and two seedheads.

Here you can see the "seeds" inside: the glumes, lemmas, and paleas.

In bright light, the panicles glisten.

Shows the soft cottony feel and the branching structure.

Individual spikelets usually show the edges of the seeds as darker spots.

Long leaves are thick around the lower part of the stem.

Roots of Arizona Cottontop

How to Identify Arizona Cottontop

  Digitaria californica grows from about knee high to shoulder high. It is a perennial plant that grows especially in late summer. If some of the spike-like panicles are 6 to 10 inches long, it feels cottony, and the "seeds" show through the furry spikelets, it is Arizona Cottontop.

Similar Species

  From a distance you might think any large, spike-like grass is Arizona Cottontop. But up close it is quite unique. The only other common, purely white-topped grasses are Cane Bluestem (Bothriochloa barbinodis) and Rabbitsfoot (Polypogon monspeliensis), each of which has much shorter seedheads.