Physocarpus capitatus

(Pursh) Kuntze

Revis. Gen. Pl. 1: 219. 1891.

Common names: Pacific nine-bark
Endemic
Basionym: Spiraea capitata Pursh Fl. Amer. Sept. 1: 342. 1813
Synonyms: Physocarpus opulifolius var. tomentellus (Seringe) B. Boivin
Treatment appears in FNA Volume 9. Treatment on page 349. Mentioned on page 348.

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

Distribution

V9 574-distribution-map.jpg

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

Discussion

Physocarpus capitatus is commonly cultivated.

Selected References

None.

Lower Taxa

None.
... more about "Physocarpus capitatus"
Crinan Alexander +
(Pursh) Kuntze +
Spiraea capitata +
Pacific nine-bark +
B.C. +, Alaska +, Calif. +, Idaho +, Oreg. +  and Wash. +
20–1300 m +
Open sunny slopes on clay (higher elevations), stream and swamp banks, lake margins in moist woods (lower elevations) +
Flowering May–Jul +  and fruiting Jul–Aug. +
Revis. Gen. Pl. +
Physocarpus opulifolius var. tomentellus +
Physocarpus capitatus +
Physocarpus +
species +