Balsamorhiza |
Balsamorhiza deltoidea |
|
---|---|---|
balsamroot |
deltoid balsamroot |
|
Habit | Herbs perennial; with thick, resin-producing taproots. | |
Stems | erect, scapose, unbranched. |
forming clumps, 14–54 cm, green, villous-hirsute, with shorter, glandular hairs. |
Leaves | mainly basal; simple or pinnately compound, lanceolate to ovate; cauline opposite, sometimes 1 additional pair of reduced cauline leaves alternate. |
simple; margins entire to toothed; teeth rounded and apiculate; surfaces abaxially sparsely hirsute, adaxially sparsely hirsute, villous-hirsute on veins; basal leaves in multiple rosettes; blades deltate, 7.5–27 × 6–16 cm, bases cordate or hastate; petioles 10–27 cm; cauline blades 3–7.5 × 1.1–2.7 cm; petioles 0–8.5 cm. |
Inflorescences | with 1 main head, occasionally with up to 6 axillary heads per stem. |
with 1 larger; terminal head and 0–2 smaller; axillary heads; peduncles 1–12 cm. |
Involucres | broadly campanulate to hemispheric. |
terminal 10–15 × 20–33 mm; axillary 8–10 × 11–17 mm. |
Receptacles | flat to convex, paleate. |
|
Ray florets | pistillate; corollas yellow or rarely pink to red. |
deciduous, 11–21 on large heads, 6–9 on small heads, yellow; rays 18–35 × 4–17 mm. |
Disc florets | bisexual; corollas yellow, 5-lobed. |
5–8 mm. |
Phyllaries | in 2–4 series; outer equaling or surpassing inner. |
ovate, 10–32 × 4–9 mm, villous; more densely so at bases; outer phyllaries often lanceolate; longer than inner. |
Fruits | 4-sided; black, glabrous or strigillose; pappi 0. |
9 × 1.5 mm, glabrous. |
Heads | radiate. |
|
Paleae | lanceolate; acute, folded around fruits. |
~7 mm. |
2n | =38. |
|
Balsamorhiza |
Balsamorhiza deltoidea |
|
Distribution | ||
Discussion | Western Canada and United States. 12 species; 10 species treated in Flora. Balsamorhiza is most closely related to Wyethia, from which it is distinguished by being scapose. Balsamorhiza is divided into two sections, both of which occur in Oregon. Section Artorhiza has cordate or sagittate, simple leaves; a taproot bearing multiple crowns; alternate stem leaves above the pair of opposite leaves; and often multiple heads per stem. Section Balsamorhiza has generally pinnately divided leaves (often simple in B. serrata); taproots bearing one or at most two crowns; one pair of opposite stem leaves; and a solitary head per stem. All species of Oregon Balsamorhiza have a chromosome number of n=19 and hybridize when they come together except for the polyploid B. macrophylla. Intersectional hybridization merely produces hybrid swarms, while intrasectional hybridization tends to produce widespread clines, leading to taxonomic confusion. Hybrid swarms are easily distinguished in the field by the wide variation in leaf division and pubescence within a given population. In the herbarium, when only one plant per population is present, hybrids are best distinguished by possessing leaves that are not as deeply divided as would be expected for the most similar-looking member of section Balsamorhiza, or by plants with pinnately divided leaves having either multiple heads per stem or alternate, in addition to opposite, stem leaves. Widths of heads are those of pressed specimens. Widths of pinnae are the width of full-sized pinnae from the middle of a fully developed leaf at their widest point (not including any lobes that may be present). |
Grasslands, pine or oak woodlands. Flowering Mar–Jul. 50–2200 m. Casc, ECas, Sisk, WV. CA, WA; north to British Columbia. Native. Balsamorhiza deltoidea grows west of the Cascade Range and intergrades with B. careyana in the Cascades and along the Columbia River. (See discussion under B. careyana.) It also hybridizes with B. sericea in Josephine County. Hybrids between Balsamorhiza deltoidea and B. hookeri have been given the name B. × terebinthacea but are not expected to be found in Oregon, given that the ranges of the parental species do not overlap here. The specific epithet refers to the deltoid shape of the leaves. |
Source | Flora of Oregon, volume 1 | Flora of Oregon, volume 2, page 199 Abigail (Abby) Moore |
Sibling taxa | ||
Subordinate taxa | ||
Web links |
|