Red is the usual color of paintbrush flowers, but castilleja flava
is one of the few yellow species, and can sometimes be pale orange. The greenish yellow bracts along the uppermost few inches of the stems are divided into long, narrow lobes (3 to 5 of them); as are the light green leaves lower down. The narrow flower tubes at the top of the plant are about one inch long, enclosed by yellow-tipped sepals. Stems are woody and have a sparse covering of narrow, grey-green leaves; most of the foliage grows around the base, forming a rather untidy cluster.