Asian Spiderflower

Plants (10–)30–100(–160) cm. Stems viscid. Leaves: petiole 1.5–4.5(–8) cm, glandular-hirsute; leaflet blade ovate to oblanceolate-elliptic, (0.6–)2–6 × 0.5–3.5 cm, margins entire and glandular-ciliate, apex acute to obtuse, surfaces glandular-hirsute. Racemes 5–10 cm (10–15 cm in fruit); bracts (often deciduous), trifoliate, 10–25 mm, glandular-hirsute. Pedicels 6–30 mm, glandular-hirsute. Flowers: sepals green, lanceolate, 5–10 × 0.8–1.2 mm, glandular-hirsute; petals arranged in adaxial semicircle before anthesis, radially arranged at anthesis, bright yellow, sometimes purple basally, oblong to ovate, 7–14 × 3–4 mm; stamens dimorphic, 4–10 adaxial ones much shorter with swelling proximal to anthers, green, 5–9 mm; anthers 1.4–3 mm; ovary 6–10 mm, densely glandular; style 1–1.2 mm. Capsules dehiscing only partway from apex to base, 30–100 × 2–4 mm, glandular-hirsute. Seeds light brown, 1.2–1.8 × 1–1.2 mm, finely ridged transversely. 2n = 20.