Physocarpus capitatus

Shrubs, to 45(–60) dm. Stems erect, sometimes suckering, angled, glabrous or finely stellate-hairy. Leaves: stipules linear to narrowly elliptic, 4 × 0.5–2 mm; petiole 1–2(–3) cm; blade broadly ovate to obovate, (3–)4–8 cm, usually as wide as long, base rounded to truncate or slightly cordate, 3- or 5-lobed, margins irregularly crenate to doubly serrate, apex obtuse to acute, abaxial surface paler, glabrous or more densely stellate-hairy, adaxial glabrous or sparsely stellate-hairy. Inflorescences 30–50-flowered, dense, hemispheric racemes, 3 cm diam., sometimes compound with some proximal pedicels becoming secondary peduncles; bracts narrowly elliptic to spatulate, 4 × 2 mm, apex acute or erose-dentate, faces glandular. Pedicels 1–1.5 cm, densely stellate-hairy. Flowers 5–8 mm diam.; hypanthium cup-shaped, 2 mm, densely stellate-hairy; sepals pale green to white, darker in center, triangular, 2–3 mm, apex gland-tipped, surfaces densely stellate-hairy; petals white, broadly elliptic to orbiculate, 3–4 × 3–4 mm; stamens equal to or exceeding petals; carpels 3–5, connate basally, mostly glabrous, sometimes hairy (on ventral suture). Follicles 3–5, connate basally, shiny brown, ovoid, 5–7 mm (lengths slightly exceeding sepals), glabrous; styles 2.5–3 mm. Seeds 2(–5), pyriform, 2.3–2.8 mm. 2n = 18.

Phenology: Flowering May–Jul; fruiting Jul–Aug.
Habitat: Open sunny slopes on clay (higher elevations), stream and swamp banks, lake margins in moist woods (lower elevations)
Elevation: 20–1300 m

B.C., Alaska, Calif., Idaho, Oreg., Wash.

Discussion

Physocarpus capitatus is commonly cultivated.

Selected References

None.

Lower Taxa