Iva microcephala Nutt.

Annuals, 10–70(–100) cm. Stems erect. Leaves: petioles 0–1 mm; blades linear to filiform, 10–35(–60) × 0.6–1.5(–3) mm, margins entire, faces ± scabrellous, gland-dotted. Heads in ± spiciform arrays. Peduncles 0.5–1 mm. Involucres hemispheric, 1.5–2 mm. Phyllaries: outer 5 distinct, ± herbaceous. Paleae cuneiform to setiform, 1–2 mm. Pistillate florets 2–3+; corollas 0.5–0.8 mm. Functionally staminate florets 3–5; corollas 1.8–2 mm. Cypselae 1–1.5 mm. 2n = 32.