It seems like the showiest flowers are usually found in grasslands. Wildflowers such as balsamroot, lupine and paintbrush that bloom in prairies can really knock your socks off compared to the delicate but inconspicuous forest twinflower and bunchberry.
However, heart-leaved arnica (arnica cordifolia) is an exception to this rule. Its large, bright yellow, sunflower-like heads can be seen in conifer forests throughout mountainous western North America, from Alaska to California and New Mexico, and one colony isolated on a peninsula in Lake Superior (how did it get there?)
There are at least 10 species of arnica growing wild in Montana, but heart-leaved arnica is the most common. The basal leaves are shaped like upside-down hearts, and it has two or three pairs of narrower stem leaves. The nodding flower heads can be found in May in foothill locations like Pattee Canyon, but higher up in the mountains you can find it blooming in June or even in July. High-elevation plants are smaller with narrower leaves. However when these alpine forms are transplanted lower down they become indistinguishable from lower elevation plants.
What many people think of as the "flowers" of arnica are actually clusters or heads of numerous small blossoms. In arnica these heads have two different kinds of flowers: The ray flowers resemble petals, and the disk flowers make up the honeycomb-like center. Each is a separate flower producing a single seed. By combining these small flowers into a large head, arnica makes a display that's more attractive to pollinating insects.
The foliage and especially the flowers of the heart-leaved arnica are sticky and produce a spicy smell. The smell is a harbinger of its medicinal qualities. European arnica (arnica montana) has been used for centuries in folk medicine, and our heart-leaved arnica is thought to have similar properties. The flowers and leaves are used to make an ointment or tincture effective at reducing the swelling and pain of bruises and sprains. Minute quantities are taken homeopathically to reduce pain and the shock of injury. Goethe, the German philosopher, poet (and botanist), is reported to have drunk arnica tea to ease the pain of heart disease. Oddly, Native Americans are not known to use this plant medicinally.
Even though I prefer to hike in open country where I can have an unobstructed view of our inspiring mountain landscapes, the showy wildflowers such as heart-leaved arnica make the forests something to look forward to as well.
Peter Lesica is a botanist associated with the University of Montana and one of the founders of the Montana Native Plant Society. The society writes a weekly column for the Missoulian Outdoors section.