Arizona Sunflower

Helianthus arizonensis is morphologically similar to the polyploid H. ciliaris; H. arizonensis is diploid (or triploid) and has entirely yellow disc corollas. It is known from relatively few sites.

Perennials, 20–30 cm (roots creeping). Stems erect to ascending, glabrous (glaucous). Leaves cauline; opposite; sessile; blades (bluish green) lanceolate, 2–7 × 0.5–1.3 cm, bases cuneate, margins entire (undulate), faces glabrous (glaucous). Heads 1–7. Peduncles 2–7.5 cm. Involucres hemispheric, 9–18 mm diam. Phyllaries 16–19, lance-ovate, 3.5–7 × 2–2.8 mm, (margins ciliate) apices acute, abaxial faces glabrate, sparingly gland-dotted. Paleae 5.5–6.5 mm, 3-toothed (apices acute, gland-dotted). Ray florets 10–14; laminae 7–9 mm. Disc florets 30+; corollas 3–3.5 mm, lobes yellow; anthers reddish brown, appendages brownish. Cypselae 2.8–3.2 mm, glabrous; pappi of 2 deltate, erose scales 1–1.7 mm. 2n = 34, 51.

Helianthus arizonensis is a North American species of sunflower known by the common name Arizona sunflower. It is native to the States of Arizona and New Mexico in the southwestern United States.

Helianthus arizonensis is a perennial herb up to 30 cm (12 inches) tall. Its leaves have no hairs. One plant produces 1-7 flower heads, each head with 10-14 yellow ray florets surrounding at least 30 yellow disc florets.