J. Arnold Arbor. 45: 419. 1964.
Shrubs, 30–80+ cm. Stems erect. Leaves mostly alternate; petioles 5–20 mm; blades ovate to rounded-deltate, 20–35 (–50) × 18–30 (–45) mm, bases broadly cuneate to ± truncate, margins toothed, abaxial faces ± densely tomentulose (between veins), adaxial faces sparsely tomentulose, glabrescent. Pistillate heads clustered, proximal to staminates; florets 2 (–3). Staminate heads: peduncles 0–3 mm; involucres ± cupshaped, 3–5 mm diam., tomentulose; florets 12–20+. Burs: bodies obconic to fusiform, 4–6 mm, tomentulose (little, if at all, stipitate-glandular), spines 15–20+, scattered or on distal 1/2, ± subulate (the proximal basally flattened), 2–3 mm, tips usually uncinate, sometimes straight. 2n = 72.
Phenology: Flowering Mar–Apr.
Habitat: Clays or sandy soils, among lava rocks
Elevation: 50–200 m
Calif., Mexico (Baja California), Mexico (Baja California Sur)