Native to Africa and Europe, in the US helminthotheca echioides
is found in scattered, low elevation regions of California, Nevada, Oregon and Washington, where it can bloom any time of year. The ribbed stems are thick and rigid, reaching heights of six feet or more, and bear many spiny, bristly leaves, which may have small lobes along the edges. Upper stem leaves may be clasping; those lower down the stem have short, winged stalks.
Flowerheads are produced in small clusters at the top of the branches; they are 1 to 1.5 inches in diameter, formed of many ligulate (ray-like) yellow florets, which have four notches at the tip. The upper undersurfaces of the florets are streaked reddish purple. The broad, green outer phyllaries (3 to 5 of them) are large and spreading, bristly and leaf-like.