Image of Mojave thistle

Description:

Inflorescence: heads in loose to crowded flat-topped or panicle-like clusters (occasionally on short axillary branches); peduncle leafy, 0--10 cm; involucre 1.5--2.5 cm, 1.5--2 cm diam, +- ovoid, +- loosely tomentose, becoming glabrous; phyllaries graduated, ovate (outer) to lance-ovate (middle), appressed, midribs often with sticky-resinous ridge, tip-spines 3--7 mm, ascending or spreading.