Sisyrinchium californicum is a rhizomatous perennial herb producing a pale green, nonwaxy stem which grows up to about 60 centimeters tall.

The herbage turns dark brown or black as it dries.

The flat, narrow leaves are grasslike.

The flower has six tepals each between 1 and 2 centimeters in length.

They are light to bright yellow, often with brown veining.

 The fruit is a dark-colored capsule.