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 Idaho Mountain Wildflowers

Rose family, Rosaceae

The rose family is large, made up of 110 genera and 3,100 species. It is well represented in our mountains by plants that range in size from tiny-flowered alpine plants to full-sized trees. The Rosaceae have in common five sepals united at the base of the flower to form a disk or cup (“hypanthium” or “hypan”) to which the petals (also usually five) and stamens ( many) are attached. Most species also have sepal-like leaves or “bracteoles” that arise from the stem just below the flowers. Fruit in the rose family takes many forms: “drupes” as in the genus Prunus (plums, apricots, almonds, peaches, cherries, etc.) and “pomes” as in the genera Malus, Pyrus, Cydonia and Eriobotrya (apples, pears, quinces, loquats). Some members of the family form multiple small “achenes” (seeds) or “drupelets” which mature into aggregate fruits such as species of Rubus (raspberries, blackberries, and similar plants); and Fragaria (strawberries). Roses, from which the family’s scientific name was derived, have been known by that, or a similar, name in European languages as far back as ancient Greece (the island of Rhodes [Rodos] was named for a rose, or similar flower).


Western chokecherry, Prunus virginiana L. var. melanocarpa (A. Nelson) Sarg. (left, right) grows in all Canadian provinces, and throughout the United States except for the deep south. The western variety, var. melanocarpa—the term means “black fruit”—is a tall bush that flowers when it is only a foot or so tall. The plants usually mature as tall bushes; rarely as trees as much as twenty feet high. The tart but edible cherries are “drupes,” fleshy fruit, with seed-containing pits. Lewis and Clark gathered specimens of western chokecherry twice, first in September of 1804 in today’s South Dakota, and again on May 29, 1806, while camped on the Clearwater River in today’s Idaho.

The eastern variety, var. virginiana differs in that it is a sizeable tree that does not flower until mature.

Mountain ash, Sorbus scopulinus Greene  (left, right) is unrelated to the true ash of the eastern United States (Fraxinus spp.). It is found in many parts of the West. Ours is a small tree that bears clusters of white flowers in late spring, ripening in late summer into colorful bunches of orange berries. Lewis and Clark collected a fruiting specimen in 1805, during their journey west (September 2nd, on the North Fork of the Salmon River) and again on Lolo Pass during their homeward journey (June 27, 1806). The closely related and very similar Sitka mountain ash, Sorbus sitchensis M. Roemer, is also found in Idaho, although at higher elevations.

Western serviceberry, Amelanchier alnifolia (Nutt.) Nutt. ex M. Roemer (left, right) The western serviceberry (also Saskatoon serviceberry) is an attractive small tree that grows throughout northern North America to mid-elevations. The species name alnifolia, means “alder-like leaf.” Its deep blue berries are edible, although they have little taste. Lewis and Clark collected a variety of the western serviceberry, var. semiintegrifolia, at The Dalles in Oregon, and then, what may have been this plant, var. alnifolia, in north central Idaho in the spring of 1806. The name Amelanchier is derived from a Savoyard term for the medlar-tree. Mespilus germanica.

It may be difficult to differentiate serviceberry from chokecherry when they are not flowering or fruiting, The leaves of both are toothed, but the service berry leaf is toothed only on the end.

Black hawthorn, Crataegus douglasii Lindl. is found from the Dakotas to the Northwest, growing to fairly high elevations. The trees may be identified by their long, sharp thorns, rounded leaves with scalloped ends, clusters of white spring-blooming flowers, and later by their dark-red, drying to black, fruit. The gnarled trees have a heavy bark and grow as much as thirty feet high. Palatable, but hardly delicious, “haws” were an important food for Native Americans. Both this, and the similar red hawthorn, Crataegus chrysocarpa, grow in Idaho—the latter as a cultivated plant.

American wild plum, Prunus americana Marshall (left, right).The American wild plum is the tastiest of all of our native Prunus species. As seen in the photographs, early blooming flowers are arranged in an attractive cluster that appears before the leaves are out. The fruit may be yellow, orange, or even, occasionally red. Its lanceolate, serrated leaves are typical of Prunus species in general. The American plum is widely distributed, found in almost all of the United States with the exception of Oregon, Nevada, Texas and California--and Idaho. Nevertheless, the trees grow in the foothills of the Clearwater Mountains near Harpster, Idaho where this one was photographed. Are they native? Or were they planted by settlers? Although not reported from Idaho, it would not be surprising if these were native trees, for Prunus americana grows nearby in western Montana and in eastern Washington.

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