10. Argythamnia mercurialina (Nuttall) Müller Arg., Linnaea. 34: 148. 1865. (as Argyrothamnia).
Tall silverbush Tall silverbush
Aphora mercurialina Nuttall, Trans. Amer. Philos. Soc., n. s. 5: 174. 1835; Ditaxis mercurialina (Nuttall) J. M. Coulter
Herbs, perennial, monoecious or dioecious, to 8 dm. Stems usually erect, rarely prostrate in var. pilosissima, hairy, hairs malpighiaceous. Leaves: stipules deciduous, subulate to ovate, 0.3–0.5 mm, margins not glandular; petiole usually absent, rarely to 4 mm on proximal leaves; blade lanceolate, elliptic, ovate to obovate, 1.5–7.5 × 0.6–3.5 cm, margins entire or serrulate, without glands, surfaces hairy, hairs malpighiaceous. Inflorescences bisexual or unisexual, to 12 cm; bracts ovate to lanceolate, 1.5–2.5 mm, margins without glands. Flowers without pink dye when wetted. Staminate flowers: sepals lanceolate to narrowly elliptic, 2.3–3 × 0.7–0.8 mm; petals elliptic to spatulate, 2–2.5 × 0.8–1 mm, free from androphore; nectary glands linear to obovate, 0.3–0.5 × 0.1–0.2 mm, free from androphore, glabrous or pubescent; stamens 8, staminodes 0. Pistillate flowers: sepals elliptic, 1–7 × 0.3–3 cm, without glands; petals 0 or 5, elliptic, linear, or punctiform, less than 0.5 mm; nectary glands linear, 0.7 × 1.5 mm, glabrous or pubescent; ovary strigose; styles 0.8–1.5 mm, pubescent; stigmas flattened. Capsules 6–14 mm, hispidulous to strigose. Seeds 3.2–4.5 mm, smooth to slightly papillate.
Varieties 2 (2 in the flora): sc United States.