Californian burr
Xanthium orientale L. (Xanthium californicum)

Herb to 2 m high; stems scabrous, unarmed.

Leaves ovate to triangular, 5–14 cm long, 5–15 cm wide, shallowly 3-lobed, base ± cordate, margins toothed, both surfaces green and scabrous, lamina with 3 main veins; petiole 3–8 cm long.

Heads inconspicuous. Burrs ellipsoid, 15–20 mm long, glandular-hairy, with numerous hooked spines 3–5 mm long, beaks diverging, incurved and hooked, 4–6 mm long.