Heliotropium marchionicum Decne., Voy. Venus & Bot.

Shrubs or suffrutescent perennials 1–2 m tall, stems erect or decumbent, sympodially branched, with usually only a single lateral branch 30–120 cm long developing adjacent to inflorescence, terete, 1.5-3 mm diam., most parts densely silvery white strigillose with ascending white trichomes 0.2–0.5 mm long. Leaves subopposite to alternate, blade elliptic to narrowly elliptic or obovate-elliptic, 1–5 × 0.5–1.5 cm, apex acute, obtuse or rounded, often apiculate, base acute to narrowly cuneate, sometimes attenuate, chartaceous to subcoriaceous, both surfaces strigillose to densely white strigillose with appressed white trichomes 0.2–0.4 mm long, smooth or sometimes pustular, secondary veins 2–3 pairs arising in basal half of lamina; petiole 3–15 mm. Inflorescences terminal and later displaced by growth of one axillary bud, or sometimes leaf-opposed, scorpioid-cymose, densely white strigillose as for stems and leaves, 4–7 cm long, forked once, peduncle 1–2 cm long, primary branches 2.5–7 cm long, each with 17–35 flowers. Flowers sessile or subsessile, calyx lobes 5, densely white strigillose, free to the base, subequal, ovate to lanceolate, 1.7–2.2 × 0.7–1.2 mm, acute to acuminate; corolla shortly funnelform, 2.6–3.2 mm, tube 2.0–2.2 mm, externally strigillose except at base, internally with pubescent lines below the lobes, lobes 5, subcircular, 1.2-1.7 × 0.8–1.3 mm × 0.8 mm, margins crisped, dorsally strigillose medially; stamens 5, attached below middle of tube, basifixed, anthers linear-oblong, 0.6–0.7 mm long, glabrous, not connate; ovary ovoid, densely strigillose, 0.5 mm long, style terminal, 0.3–0.6 mm long, glabrous, stigmatic column 0.4–0.5 mm, cylindrical-conical, papillose, apex strigillose, base annular. Fruit broadly ovoid, 1.5–2.0 × 2.0 mm, shallowly 4-lobed, externally strigillose, dry, splitting into 4 wedge-shaped nutlets. Nutlets 1.4–1.6 × 0.8–1.0 mm, apiculate, dorsally densely strigillose, ventrally glabrous, dark brown.

Marquesas Islands, known only from Nuku Hiva.