Rocky Mountain iris is a perennial herb, with large, attractive, blue flowers 

 on long succulent stalks from thickened, dark, fibrous-coated, underground 

 rootstocks. It occurs from North Dakota to New Mexico, southern California, 

 and British Columbia and is the only species of Iris indigenous to the far 

 Western States except for the three Pacific States, where other species are 

 found. It appears chiefly in bottomlands or moist situations, in meadows and 

 parks, at elevations upward to 10,000 feet. It generally grows in small clumps 

 or patches but, under favorable conditions, may occur in dense, nearly pure 

 stands of considerable size. It also frequently grows in such sites as gravelly 

 hillsides which dry out during the summer. 



Rocky Mountain iris is worthless as a forage plant but, when its stand is 

 increasing, it may be an indicator of overgrazing, as its robust underground 

 rootstocks enable it to withstand trampling and to spread rather rapidly when 

 other vegetation is weakened. This species, when once extensively established, 

 greatly retards the revegetation of the range by more palatable plants. It is 

 a good soil binder, but ordinarily grows in moist soils which are potentially 

 capable of supporting other plants of equal soil-holding qualities and of greater 

 forage value. 



This species flowers from May to July, depending on latitude and elevation. 

 If moisture is available the plants remain green throughout the summer, 

 otherwise they dry up in midsummer after the seed matures. 



IRISES (I'ris spp.) 



Iris is a large genus of herbaceous plants of north temperate regions, 

 well known because of their attractive blossoms. Other common names are 

 flag, flag-lily, snake-lily, and water-flag. A great variety and number of 

 species occur in the southeastern United States, but the genus is rather poorly 

 represented in the Western States, where only nine native species occur, eight 

 of which grow exclusively in the Pacific Coast States. Generally, irises are 

 found in moist to wet sites, or in situations where plenty of moisture is present 

 early in the season during the main growth period, despite that such sites 

 subsequently become very dry. However, the distribution of irises in the 

 West is spotted rather than general, although these species frequently are 

 so abundant on favorable sites that they form nearly pure stands. 



Irises are worthless as forage plants. They are sometimes important obsta- 

 cles to range improvement, in that they tend to increase on overgrazed areas 

 adapted to their growth, and when once established greatly retard the regen- 

 eration of palatable forage species. 



The genus is of considerable importance commercially, as many species are 

 grown extensively as ornamentals. The American Iris Society has recognized 

 some 2,300 named commercial varieties and hybrids which have been developed 

 through intensive cultivation. 1 



The Indians formerly used the tough, flexible fibers from the leaf margins of certain 

 species, such as Oregon iris (/. tenax). in making strong twine for snares and nets. They 

 also used the rhizomo, or "root" of blueflag iris (T. versicolor). the most widespread species 

 in the eastern United States, as a remedy for stomach disorders, and are reputed to have 

 grown this plant for its medicinal value. 2 Both Indians and whites used this species as 

 an alterative, diuretic, and purgative (op. cit.). An extract of the root was also used as 

 a remedy for dropsy and is listed as an official drug in the United States Dispensatory. 3 

 The rhizome in the fresh state possesses considerable potency as a cathartic and emetic. 

 It has no odor, hut the taste is acrid and nauseous. An analysis of the roots of this 

 species disclosed that the principal compounds are yellow oil, isophthalic acid, salicylic 

 acid, tannin, sugar, and resins containing fatty acids. 4 The rhizomes of Florentina iris 

 (/. germanica, syn. I. florentina) and of sweet iris (/. pallida) are used in the prepara- 

 tion of orrisroot, which is imported chiefly from Leghorn, a province in Italy. This 

 product is used in medicine, as a sachet powder, for dry shampoos, and for cleaning teeth. 



1 American Joint Committee on Horticultural Nomenclature. STANDARDIZED PLANT 

 NAMES . . . Prepared by F. L. Olmsted, F. V. Coville, and H. r. Kelsey. 546 pp. 

 Salem, Mass. 1923. 



2 Henkel, A. AMERICAN ROOT DRUGS. U. S. Dept. Agr., Bur. Plant Indus. Bull. 107, 

 80 pp., illus. 1907. 



3 Remington, J. P., Wood, H. C., Jr., Sadtler, S. P., La Wall, C. H., Kraemer, H., and 

 Anderson, J. F. THE DISPENSATORY OF THE UNITED STATES OF AMERICA, by Dr. Geo. B. 

 Wood and Dr. Franklin Bache. Ed. 20. thoroughly rev. and largely rewritten . . . 

 2,010 pp. Philadelphia and London. 1918. 



4 Power, F. B., and Salway, A. H. THE CONSTITUENTS OF THE RHIZOME OF IRIS VERSI- 

 COLOR. Amer. Jour. Pharin. 83 : 1-14. 1911. 



