Serviceberries were well known to the men of the expedition. Numerous species grow in North America, and their berries, although not much used today, were in the past eaten fresh, dried, made into preserves, and used to make wine. The men of the expedition had been seeing the western serviceberry (or saskatoon, Amelanchier alnifolia) all across the country. Lewis mentioned it (usually as "Sarvis berry") as growing along the upper Missouri in notes that he compiled in Fort Mandan during the winter of 1804-1805. On July 17th, 1805, above the Great Falls of the Missouri, he noted that "The survice berry differs somewhat from that of the U' States the bushes are small sometimes not more than 2 feet high and scarcely ever exceed 8 and are proportionably small in their stems, growing thicly ascosiated in clumps. The fruit is the same form but for the most part larger more lucious and of so deep a perple that on first glance you would think them black."

Western serviceberries (Amelanchier alnifolia var. alnifolia) are attractive plants. Their white, five-petaled flowers, born in clusters at the ends of the branches, bloom early in the spring. They have found their way into gardens and in the west have replaced the related shadbush (or eastern serviceberry, Amelanchier canadensis) as ornamental plants. The tree takes its name from the related European service tree, also a member of the rose family. The name is probably a corruption of the Latin name for the European tree, sorbus. The alternate use of the work sarvis presumably had a similar derivation. In the Chesapeake Bay region, the appearance of the flowers signified that the shad had started to run, which gave rise to another common name, "shadbush." The scientific name, Amelanchier, was adopted from Amelancier, the Savoyard word for the European medlar tree, Mespilus germanica. The species name, alnifolia, means "alder-leaved," for the shape of the leaves.

Western serviceberries grow throughout northern North America, from Alaska to Nevada, mostly east of the Cascade Range and the Sierra Nevada, through the Rocky Mountains and Great Plains to Quebec. They vary in size from small shrubs to attractive trees, occasionally as much as twenty feet high. Their foliage characteristically -- as with an identifiable specimen in the Lewis and Clark Herbarium -- consists of broad, dark green leaves with serrated ends or margins. Given the plant's wide distribution, it is not surprising that there are several varieties. The plant that Lewis collected on the Columbia is Amelanchier alnifolia var. semiintegrifolia, the Cascade serviceberry. A second specimen, collected on the Clearwater River several weeks later, consists of only two twigs. Although it is probably a serviceberry, its identification remains uncertain.

-from Chapter 7, "Fort Clatsop to Camp Chopunnish"