OregonFlora: Balsamorhiza macrophylla vs. Balsamorhiza sagittata

	Balsamorhiza macrophylla	Balsamorhiza sagittata
	large-leaf balsamroot	arrowleaf balsamroot
Stems	up to 35 cm, tomentose; from single taproot.	forming clumps, 20–65 cm, gray-tomentose.
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.	simple; ovate, bases cordate or sagittate; margins entire; surfaces tomentose; more densely so abaxially than adaxially; basal leaves in multiple rosettes; blades 7–27 × 4.5–14.5 cm; petioles 8–39 cm; cauline blades 3–5.5 × 0.5–0.9 cm; petioles 0.7–5.5 cm.
Inflorescences	with 1 terminal head.	with 1 larger; terminal head; and rarely 1–3 smaller; axillary peduncles 0.2–13 cm.
Involucres	14–18 × 25–30 mm.	terminal 10–15 × (10)15–30 mm; axillary 8 × 8–12 mm.
Ray florets	14–16, yellow; rays 35–40 × 8–11 mm.	8–19 on large heads, 5–9 on small heads, yellow; rays 25–40 × 7–18 mm.
Disc florets	~9 mm.	6–8 mm.
Phyllaries	ovate-lanceolate, 20–25 × 5–6 mm; tips acuminate, tomentose.	lanceolate, 10–32 × 3–7 mm; outer often longer, densely tomentose, especially basally.
Fruits	8–9 mm, glabrous.	6–7 × 1.2–2 mm, glabrous.
Paleae	10–12 mm.	9–11 mm.
2n	=100 ± 2.	=38.

	Balsamorhiza macrophylla	Balsamorhiza sagittata
Distribution	[WildflowerSearch map] [BONAP county map]	[WildflowerSearch map] [BONAP county map]
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.	Open areas, edges of forests, open woodlands. Flowering Apr–Jul. 300–2100 m. BR, BW, Col, ECas, Owy. CA, ID, NV, WA; north to British Columbia, northeast to Alberta, east to SD, southeast to AZ. Native. This is the most widespread species of Balsamorhiza. It hybridizes with every species of section Balsamorhiza with which its range overlaps but is itself morphologically quite uniform and easy to distinguish from the other members of section Artorhiza. Its hybrids with B. incana have been given the name B. × tomentosa.
Source	Flora of Oregon, volume 2, page 200 Abigail (Abby) Moore	Flora of Oregon, volume 2, page 201 Abigail (Abby) Moore
Sibling taxa	B. careyana, B. deltoidea, B. deltoidea x Balsamorhiza sericea, B. hispidula, B. hookeri, B. incana, B. lanata, B. rosea, B. sagittata, B. sericea, B. serrata	B. careyana, B. deltoidea, B. deltoidea x Balsamorhiza sericea, B. hispidula, B. hookeri, B. incana, B. lanata, B. macrophylla, B. rosea, B. sericea, B. serrata
Synonyms	Balsamorhiza hookeri var. idahoensis
Web links	Local floras: OR Local Web sites: Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog. WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Balsamorhiza sagittata

large-leaf balsamroot

arrowleaf balsamroot

Stems

up to 35 cm, tomentose; from single taproot.

forming clumps, 20–65 cm, gray-tomentose.

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.

simple; ovate, bases cordate or sagittate;

margins entire;

surfaces tomentose; more densely so abaxially than adaxially;

basal leaves in multiple rosettes;

blades 7–27 × 4.5–14.5 cm;

petioles 8–39 cm;

cauline blades 3–5.5 × 0.5–0.9 cm;

petioles 0.7–5.5 cm.

Inflorescences

with 1 terminal head.

with 1 larger; terminal head; and rarely 1–3 smaller; axillary peduncles 0.2–13 cm.

Involucres

14–18 × 25–30 mm.

terminal 10–15 × (10)15–30 mm; axillary 8 × 8–12 mm.

Ray florets

14–16, yellow;

rays 35–40 × 8–11 mm.

8–19 on large heads, 5–9 on small heads, yellow;

rays 25–40 × 7–18 mm.

Disc florets

~9 mm.

6–8 mm.

Phyllaries

ovate-lanceolate, 20–25 × 5–6 mm;

tips acuminate, tomentose.

lanceolate, 10–32 × 3–7 mm; outer often longer, densely tomentose, especially basally.

Fruits

8–9 mm, glabrous.

6–7 × 1.2–2 mm, glabrous.

Paleae

10–12 mm.

9–11 mm.

=100 ± 2.

=38.

Balsamorhiza sagittata

Distribution

[WildflowerSearch map]

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

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.

Open areas, edges of forests, open woodlands. Flowering Apr–Jul. 300–2100 m. BR, BW, Col, ECas, Owy. CA, ID, NV, WA; north to British Columbia, northeast to Alberta, east to SD, southeast to AZ. Native.

This is the most widespread species of Balsamorhiza. It hybridizes with every species of section Balsamorhiza with which its range overlaps but is itself morphologically quite uniform and easy to distinguish from the other members of section Artorhiza. Its hybrids with B. incana have been given the name B. × tomentosa.

Source

Flora of Oregon, volume 2, page 200
Abigail (Abby) Moore

Flora of Oregon, volume 2, page 201
Abigail (Abby) Moore

Sibling taxa