July 8: Mah-pah-pah ah-zhah

"Medicine River"

To see labels, point to the photo.

interactive aerial view of a high plains river and valley

© 2001 Airphoto, Jim Wark. All rights reserved.

Shortly after crossing the Dearborn River, Lewis saw that the Indian road "continued along the foot of the mountain to the West of north"—possibly the ancient way now known as the Old North Trail—so he and his men cut northeast across the "tolerably level" plain towad the Sun ("Medicine") River. His aim was to "hunt down it to it's mouth in order to procure the necessary skins to make geer, and meat for the three men whom we mean to leave at the falls." He and Clark had first heard of this river at Fort Mandan during the winter of 1804-05. Above the Falls of the Missouri,

a large stream called Mah-pah-pah,-ah-zhah, or Medecine river falls in on the N. side. This river heads in the Rocky Mountains opposite to a river which also takes it's rise in the same mountains and which running West discharges itself into a large river, which passes at no great distance from the Rocky mountains, running from N to South. It passes through a mountainous, broken and woody country. Not navigable in consequence of it's rapidity and shoals.

He himself had assessed the qualilties of the lower few miles of the Medicine River on the previous June 14:

found it a handsome stream, about 200 yds. wide with a gentle current, apparently deep, it's waters clear, and banks which were formed principally of darkbrown and blue clay were about the hight of those of the Missouri or from 3 to 5 feet; yet they had not the appearance of ever being overflown, a circumstance, which I did not expect so immeidately in the neighbourhood of the mountains, from whence I should have supposed, that sudden and immence torrants wouild issue at certain seasons of the year; but the revverse is absolutely the cast. I am therefore compelled to beleive that the snowey mountains yeald their warters slowly, being partially effected every day by the influence of the sun only, and never suddonly melted down by haisty showers of rain.

Now, as he approached the same river at about 65 miles above its mouth, he studied the valley in more detail. "The land of neither the plains nor bottoms is fertile," he observed. "It is of a light colour intermixed with a considerable proportion of gravel." The grass, he added, averaged only nine inches in height.


Blue grama

Grass with purple seeds making a fan

© 2000 W. Steve Sherman, Lone Wolf Photography

The distinctive flowers of blue grama grass resemble bushy eyebrows. Grama is a Spanish word for grass.

Lewis was back in the mixed prairie ecosystem, where only short-stemmed, deep-rooted grasses can survive. Some authorities refer to it as the short grass prairie, which extends from the Rocky Mountain Front to central North Dakota.1 Here, at its western margin, the annual precipitation averages between 10 and 14 inches, most of it falling between May and July, with successive years of severe drought occurring periodically. It is so dry, in fact, that trees will not grow except on the margins of rivers and major streams. Three of the most abundant of species in the mixed grass prairie were blue grama, bluebunch wheatgrass, and needlegrass.

Blue grama (Bouteloua gracilis) consists of leaves up to six inches long, and stems up to 20 inches. The genus, pronounced Boo-til-loo-ah, was named for Claudio Boutelou (1774-1842), a professor of agriculture in Madrid, Spain. The specific epithet, gracilis, pronounced gra-sill-iss, means "slender," in reference to its leaves.


Needle-and-thread grass

Tall, brown grass with wispy tops

© 2000 W. Steve Sherman, Lone Wolf Photography

When the mixed grass prairie is over-grazed, prickly-pear cactus invades, as seen in this photo.

Needle-and-thread grass (Stipa comata) or speargrass, is the tallest of the three, its culms (stalks) reaching from one to three feet above ground, though its leaves are only four to 12 inches high. Its roots may extend more than 50 inches into the earth. The genus name, Stipa (sty-pa) comes from a Greek word meaning "tow" or "fiber," from the feathery appearance of the tips of the stalks. The name of this species, comata, is Latin for "long hair." The whispy, corkscrew-shaped parts are called awns. Each has a needle-pointed seed at one end. When the awns fall away they land seed-first on the ground. Wind spins the awn, driving the seed into the ground. 2

Farmers and ranchers who settled in the Sun River valley in the 1890s began impounding reservoirs and digging irrigation systems to deliver water supplies to hayfields steadily throughout the growing season. Those systems consisted of deep trunk ditches feeding shallower laterals where headgates controlled the rate of surface distribution to the crops. Today, a variety of more efficient systems, fed from either ditches or wells, include center-pivot sprinklers such as those that created the circular patterns pictured above.3 Unfortunately, they are severely reducing the level of the aquifer they drawn upon.

"Much rejoiced at finding ourselfes in the plains of the Missouri which abound with game," Lewis crowed. "R. Fields killed a fine buck and a goat [pronghorn]; Josh. Fields saw two buffaloe below us some distance which are the first that have been seen. we saw a great number of deer goats and wolves as we passed throuth the plains this morning but no Elk or buffaloe . . . I killed a very large and the whitest woolf I have seen."


1. Robert G. Bailey, "Description of the Ecoregions of the United States." USDA Forest Service Misc. Pub. 1391 (1995).

2. John E. Taylor and John R. Lacey, Range Plants of Montana (Bozeman: Montana State University Extension Service, 1994). Michael Champion,"Stipa comata Trin. & Rupr.,"http://www.usask.ca/agriculture/plantsci/classes/range/stipacomata.html, accessed April 6, 2005.

3. Descriptions and photographs of the various types of irrigation systems now in use will be found on the University of Georgia College of Agricultural and Environmental Sciences, Cooperative Extension Service web site, at http://pubs.caes.uga.edu/caespubs/pubcd/B882.htm.

Funded in part by a grant from the Montana Cultural Trust