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Idaho Mountain Wildflowers
Aster (Sunflower) Family: Asteraceae
Yellow daisy-like flowers
|Its little wonder that botanists refer to yellow-flowered
members of this family as "DYCs" ( "damned yellow composites") because
many are so similar that they are difficult to identify. Yellow-flowered
composites are also so common in our mountains that we can't show them
all. Instead we'll include representative examples--in no particular
order--of the more common genera.
Scabland fleabane, Erigeron bloomeri A. Gray (left). As the name suggests, the scabland fleabane is grows in barren, rocky sites in the mountains and foothills. It is characterized by narrow basal leaves and naked stems that each bear a single rayless flowerhead. The species name honors California botanist, Dr. Hiram Green Bloomer (1819-1874), who collected the plant in Nevada, near Virginia City.
Line-leaf daisy, Erigeron linearis (Hook.) Piper (right). The line-leaf daisy (also known as the desert yellow fleabane) is, like the cutleaf daisy shown on the previous pag, a small plant that grows in discrete clumps. It prefers exposed gravelly slopes where it often grows in profuse numbers from late spring into the summer, as high as tree-line. As with many plants that are adapted to dry places, both leaves and stems feel brittle. The common and scientific species names describe its thin linear leaves.
|Yellow Mules-ears, Wyethia
amplexicaulis (Nutt.) Nutt. The yellow
mules-ears (left) bears some resemblance to the arrowleaf balsam-root
shown on the right. Both are large plants with showy blooms although this
one prefers wet meadows rather than dry hillsides. Unlike the balsamroot,
it has stemless leaves (amplexicaulis meansstem-clasping).
Further, its leaves are shiny, sometimes described as having a "varnished"
appearance. Yellow mules-ears bloom in the spring, usually a week or so after
the white mules-ears shown on the previous page. Boston businessman Nathaniel
Wyeth (18021856) collected both wyethias (and other plants as well)
for botanist Thomas Nuttall, while in todays western Montana in 1833.
The Arrowleaf Balsamroot, Balsamorhiza sagittata (Pursh) Nutt., blooms in discrete clusters on hillsides where it is easily identified by its grey-green leaves and large flowers, Look for it from early in the spring well into summer, growing ever higher, its visible bright yellow patches acting almost as contour lines. Both its common and scientific names are derived from the plant's silvery arrow-shaped leaves and the roots' balsam-like odor. Native Americans are said to have eaten the plants roots; animals browse on its leaves. Lewis and Clark collected this plant twice, first in Oregon and then in Montana, during he spring and summer of 1806.
|Hookers balsamroot, Balsamorhiza
hookeri (Hook.) Nutt. var. hispidula (Sharp)
Cronquist (left). Hookers balsamroot is found in
many places in the West. Six varieties are recognized; some are quite localized
in distribution. The plant shown here was photographed in southern Idaho.
It is a small plant with pinnate (feather-like) leaves. Its stems and leaves
are hairy, as its name hispidula (covered with stiff hairs)
suggests. This variety tends to have twice pinnate
Largeleaf balsamroot, Balsamorhiza macrophylla Nutt. Although the arrowleaf is by far the most prevalent species of balsamroot, there are nine other western species. The plant shown on the right, the largeleaf balsamroot (also cutleaf balsamroot), is a Great Basin species, crossing into Idaho. It is similar to the arrowleaf balsamroot, differing chiefly in the shape of its large, incised, pinnate leaves. The species name, from the Greek, reflects its common name, large-leaf.
|The Heartleaf Arnica, Arnica cordifolia
Hook. (left). The origin of the word Arnica is unknown;
cordifolium means "heartshaped". The heartleaf arnica blooms
from late spring into summer, usually in the shade of open woods. Its stems
lie on the ground, turning upward to the flower. Arnicas typically have
relatively few (8 or so), regular rays and a well defined disk. They contain
arnicin, a rubefacient, and a tincture of the European plant, Arnica
montana, has been used topically for centuries to treat sprains and similar
The Streambank arnica, Arnica lanceolata Nutt. (formerly Arnica amplexicaulis Nutt.). The arnica shown on the right usually grows along the banks of mountain streams--the one shown here was photographed beside a seasonal rivulet high in the White Cloud Mountains in Central Idaho. As with another amplexicaulis, the yellow mule's ears shown above, the base of the leaves wraps around the stem of the plant.
Note: Most arnicas are fairly tall plants (the heartleaf arnica, and the small slender arnica are exceptions). They can usually be identified, at least generically, by their opposing leaves and relatively few-rayed flower heads.
|Twin arnica, Arnica sororia Greene
(left). The twin arnica takes its species name from the Latin
word for sister presumably because two (or more) flowerheads
arise from a common stem. It has a cluster of large basal leaves and smaller
opposed, lanceolate, stem leaves. This is a meadow plant that grows to fairly
high elevations. The twin arnica is closely related to a similar, taller
and larger-leaved species (shining arnica, Arnica fulgens Pursh; not
shown) that has much the same range throughout our western mountain states
and Canadian provinces. Until recently the species shown here was considered
to be a varietal form of the larger plant.
Spear-leaf arnica, Arnica longifolia D. C. Eaton.(right). The spear-leaf arnica is a high altitude, cluster-forming composite. It blooms in mid-August, usually close to water. The plants preference for sheltering rocks, its proximity to water, and its long, opposing, pointed leaves (responsible for both common and specific names) set it apart from other high altitude clustered composites.
Note: Arnicas tend to grow in their own place and this can also help in identifying them; e.g., Arnica gracilis grows high, Arnica sororia favors meadows, Arnica cordifolia is found in open forests, etc. (True of many other plants, of course, but especially for this genus.)
|Slender arnica, Arnica gracilis
Rydb. (left). Arnica gracilis (formerly Arnica
latifolia var. gracilis) is a plant whose habitcluster-forming,
low-growing, nestled among rocksis typical of many alpine and subalpine
plants. As illustrated, it is at home on rocky ground. The rocks protect
the plants and hold the suns heat. By looking at the plants closely,
one can see that small, broadly lanceolate leaves arise opposite each other,
typical of arnicas in general.
Hairy arnica, Arnica mollis Hook. (right) is another commom arnica that grows, often in large aggregations, from mid-elevations nearly to treeline. It's flowerheads are large with relatively few rays. The leaves are covered with fine hair (mollis means "soft" in Latin) that gives them a slightly grayish appearance. The plants range from the western provinces of Canada as far south as Colorado and west to California.
|Chamisso's (or leafy) arnica, Arnica
chamissonis Less. (left)
is found in all of our western states, and in most Canadian provinces. The
plants usually grow in moist--or recently moist --meadows to fairly high
elevations. They are characterized by their several few-rayed flowerheads,
and opposing leaves--the latter a characteristic of arnicas in general. In
common with many other widely distributed plants, several varieties are
recognized. These differ in the extent of hairiness, leaf width, and presence
or absence of toothed leaves. Ours appears to be var. foliosa (Nutt.)
Western goldentop, Euthamia occidentalis Nutt. (right). Until recently this plant was classified as the western goldenrod, Solidago occidentalis (Nutt.) Torr. & A. Gray. It has recently has been reclassified as a Euthamia (a goldentop) as originally described by Thomas Nuttall. It is very much a goldenrod-like plant, however, with small multi-rayed flowers arranged in large upright clusters. Its leaves are serrate (saw-toothed). The plants are found throughout the West, ranging as far east as the plains states.
|Meadow Goldenrod, Solidago lepida
salebrosa (Piper) Semple (left). The
meadow goldenrod, (formerly Solidago
canadensis), is distributed
over much of the United States and Canada. It blooms in open places to fairly
high elevations from midsummer on, usually in moist soil. The generic name
Solidago was derived from two Latin words, solidus meaning
complete and ago meaning I make, for the European
goldenrod (S. virgaurea L.) was valued as a
vulnerarya substance able to heal external wounds. This
plant's varietal name, salebrosa, means "rough." Although hard to
see in the photograph,,the meadow goldenrod does have ray flowers, but they
The rays are more obvious on the Mountain Goldenrod, Solidago multiradiata Aiton (right). It is also a summer blooming plant, commonly seen along our trails where the ground is moist. The plant, as it occurs in Idaho, is encountered at higher altitudes, although as one goes further northin Canada, Alaska and Siberia--it is found at progressively lower elevations. Unlike the meadow goldenrod, the flower clusters do not droop,
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