Balsamorhiza macrophylla |
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cutleaf balsamroot, Idaho balsamroot, large-leaf balsamroot |
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Habit | Plants 30–45(–100) cm. |
Basal leaves | green, ovate to lanceolate, 20–50+ × 8–15 cm (pinnatifid, lobes lanceolate, 20–80+ × 10–40 mm, entire or ± dentate), bases ± cuneate, ultimate margins usually entire (plane or weakly revolute, ciliate), apices obtuse to acute, faces scabrous or piloso-hirtellous to pilose (at least abaxial usually gland-dotted as well). |
Heads | usually borne singly. |
Involucres | ± hemispheric, 20–30 mm diam. |
Ray laminae | 35–50+ mm. |
Outer phyllaries | lance-ovate or lanceolate to lance-linear, 12–30(–40) mm, equaling or surpassing inner (margins ciliate), apices acute to attenuate. |
2n | = 100 ± 2. |
Balsamorhiza macrophylla |
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Phenology | Flowering May–Jul. |
Habitat | Deep soils, rocky meadows, sagebrush scrublands, conifer forests |
Elevation | 1000–2400 m (3300–7900 ft) |
Distribution |
ID; UT; WY
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Discussion | Balsamorhiza macrophylla is a high polyploid; it occurs sympatrically with B. sagittata. It evidently arose from hybridization between B. sagittata and B. hispidula. Balsamorhiza macrophylla has the multi-branched caudices and massive taproots of the former, and the leaf dissection of the latter. No hybrids with other species are known. Presumably, the high-polyploid chromosome complement precludes interbreeding. Plants of var. idahoensis are smaller, are known only from southwestern Idaho and northeastern Utah, and differ from var. macrophylla by being pilose, with strongly shaggy-pilose involucres. More study may determine that var. idahoensis merits specific rank. The Utah populations are not well understood and deserve attention. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 21, p. 98. |
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Ecliptinae > Balsamorhiza > subg. Balsamorhiza |
Sibling taxa | |
Synonyms | B. hookeri var. idahoensis, B. macrophylla var. idahoensis |
Name authority | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 350. (1840) |
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