Balsamorhiza macrophylla |
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large-leaf balsamroot |
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Stems | up to 35 cm, tomentose; from single taproot. |
Leaves | lanceolate-oblong, 1-pinnately divided; pinnae toothed, with teeth only on lower margins; surfaces tomentose; basal leaves in 1–few rosettes; blades 12–22 × 6–8 cm; pinnae 10–36 mm wide; petioles 7–20 cm; cauline blades 1.5–5 × 0.3–0.9 cm; petioles 6–9 cm. |
Inflorescences | with 1 terminal head. |
Involucres | 14–18 × 25–30 mm. |
Ray florets | 14–16, yellow; rays 35–40 × 8–11 mm. |
Disc florets | ~9 mm. |
Phyllaries | ovate-lanceolate, 20–25 × 5–6 mm; tips acuminate, tomentose. |
Fruits | 8–9 mm, glabrous. |
Paleae | 10–12 mm. |
2n | =100 ± 2. |
Balsamorhiza macrophylla |
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Distribution | |
Discussion | Dry, open areas. Flowering May–Jul. 700–1400 m. BW. ID; east to WY. Native. True B. macrophylla is a decaploid centered on the Wasatch Mountains in Utah and Idaho. The plants in Oregon and western Idaho are also high polyploids, but they differ morphologically from classic B. macrophylla in their denser pubescence and the shape of their leaves. These eastern plants have been given the name B. macrophylla var. idahoensis. However, further study will likely show that they have a different parentage than B. macrophylla s.s. The specific epithet “macrophylla” means large-leaved, as the leaves are much larger than those of the other members of section Balsamorhiza. |
Source | Flora of Oregon, volume 2, page 200 Abigail (Abby) Moore |
Sibling taxa | |
Synonyms | Balsamorhiza hookeri var. idahoensis |
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