Balsamorhiza macrophylla
Balsamorhiza subg. Balsamorhiza
cutleaf balsamroot, Idaho balsamroot, large-leaf balsamroot
relatively slender, bark relatively thin, not corrugated;
rhizomes sometimes present (relatively short, deep-seated);
caudices seldom branched.
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 mostly lanceolate, lance-elliptic, lance-ovate, linear-oblong, oblong, or ovate, often 1–2-pinnatifid or -pinnately lobed, sometimes cordate, ultimate margins usually crenate, dentate, or serrate, seldom entire.
mostly proximal to mid stems.
mostly shorter than leaf blades.
± hemispheric, 20–30 mm diam.
mostly yellow (becoming brick red and chartaceous in B. rosea).
35–50+ mm.
lance-ovate or lanceolate to lance-linear, 12–30(–40) mm, equaling or surpassing inner (margins ciliate), apices acute to attenuate.
usually borne singly.
= 100 ± 2.
Balsamorhiza macrophylla
Balsamorhiza subg. Balsamorhiza
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.)
Species 9 (9 in the flora).
Members of subg. Balsamorhiza usually inhabit shallow, rocky soils.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
