Shrubs, 20 dm. Stems spreading, brown becoming grayish black, glabrous or finely stellate-hairy. Leaves: stipules oblong to elliptic or obovate, 6 × 2.5 mm, base broad, apex rounded and erose to apiculate or acute; petiole 1–2.5 (–3) cm; blade broadly ovate to orbiculate, 2–6 × 2.5–6 cm, sometimes wider than long, base truncate to slightly cordate, 3-lobed or 5-lobed, clefts between lobes may shallow to deep, margins doubly crenate to doubly serrate, apex rounded, obtuse, or acute, surfaces glabrous or sparsely stellate-hairy (more so on abaxial veins). Inflorescences 15–20-flowered, fairly dense, hemispheric racemes, 2.5–4 cm diam.; bracts narrowly obovate to spatulate, 4.5 mm, apex erose or acute. Pedicels 8–15 mm, densely stellate-hairy. Flowers 5–8 mm diam.; hypanthium campanulate, 1.5–2 mm, densely stellate-hairy; sepals triangular to ovate, 2–3 mm, apex gland-tipped, surfaces densely stellate-hairy; petals white, broadly elliptic to obovate or orbiculate, 4.5 × 4.5 mm; stamens ca. 30, equal to or slightly exceeding petals; carpels 2 (3), connate at least 1/2 their lengths, densely stellate-hairy. Follicles 2 (3), ovoid, flattened, 2.5 mm (lengths not exceeding sepals), keeled apically, densely stellate-hairy, hairs white; styles 2.5–3 mm. Seeds 1 or 2, pyriform, 1.5 mm.

Phenology: Flowering May–Jul; fruiting Aug.
Habitat: Rocky canyon slopes and cliffs, open grassy slopes, dry open forests among Pinus, Juniperus, Pseudotsuga, Picea, and Populus
Elevation: 500–2800 m

Distribution

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• Legacy Map

Alta., B.C., Colo., Idaho, Mont., Nev., Oreg., Utah, Wash., Wyo.

Discussion

Physocarpus malvaceus deserves to be more widely cultivated.

Selected References

None.

Lower Taxa

None.

"sometimes wider than long" is not a number."dm" is not declared as a valid unit of measurement for this property.