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cutleaf balsamroot, Idaho balsamroot, large-leaf balsamroot

silky balsamroot, silvery balsamroot

Habit Plants 30–45(–100) cm. Plants 10–30(–40) 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).

blades silvery, lanceolate or lance-ovate, 9–30 × 2–7 cm (1-pinnatifid, lobes oblong to oblanceolate, 5–35 × 3–17 mm), bases cuneate, ultimate margins usually entire (plane or weakly revolute, obscurely, if at all, ciliate), apices rounded to acute, faces densely sericeous.

Involucres

± hemispheric, 20–30 mm diam.

campanulate to hemispheric, 11–20+ mm diam.

Ray laminae

35–50+ mm.

15–20 mm (adaxially puberulous on veins).

Outer phyllaries

lance-ovate or lanceolate to lance-linear, 12–30(–40) mm, equaling or surpassing inner (margins ciliate), apices acute to attenuate.

broadly ovate to triangular-ovate, 12–20 mm, slightly surpassing inner, apices acuminate to attenuate (margins not ciliate).

Heads

usually borne singly.

borne singly.

2n

= 100 ± 2.

Balsamorhiza macrophylla

Balsamorhiza sericea

Phenology Flowering May–Jul. Flowering Apr–May.
Habitat Deep soils, rocky meadows, sagebrush scrublands, conifer forests Serpentine outcrops, among surface rocks, in crevices, hillsides, dry streamsides among cobbles
Elevation 1000–2400 m (3300–7900 ft) 400–1800 m (1300–5900 ft)
Distribution
from FNA
ID; UT; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR
[WildflowerSearch map]
[BONAP county map]
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.)

Balsamorhiza sericea hybridizes with B. deltoidea.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 21, p. 98. FNA vol. 21, p. 96.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Ecliptinae > Balsamorhiza > subg. Balsamorhiza Asteraceae > tribe Heliantheae > subtribe Ecliptinae > Balsamorhiza > subg. Balsamorhiza
Sibling taxa
B. careyana, B. deltoidea, B. hispidula, B. hookeri, B. incana, B. lanata, B. macrolepis, B. rosea, B. sagittata, B. sericea, B. serrata
B. careyana, B. deltoidea, B. hispidula, B. hookeri, B. incana, B. lanata, B. macrolepis, B. macrophylla, B. rosea, B. sagittata, B. serrata
Synonyms B. hookeri var. idahoensis, B. macrophylla var. idahoensis
Name authority Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 350. (1840) W. A. Weber: Phytologia 50: 358. (1982)
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