Chemotaxonomic methods have recently been used to study taxa within the Tridenta- 

 tae. Chromatographic investigations by Holbo and Mozingo (1965) , Young (1965) , Winward 

 and Tisdale (1969) , Hanks and others (1971) , and Brunner (1972) give support to the 

 taxonomic treatment of species and subspecies by Hall and Clements (1923) and Beetle 

 (Beetle 1960; Beetle and Young 1965). Identification and distribution of leaf phenols, 

 sesquiterpene lactones, and alkanes are proving to be of value in delimitating Artemisia 

 species (Shafizadeh and Melnikoff 1970; Shafizadeh and others 1971; Bachelor and 

 others 1972) . 



Our special interest in sagebrush arose primarily from questions as to why game 

 and livestock exhibited marked preferences for certain big sagebrush populations 

 (Brunner 1972) or for certain individuals in a population (fig. 1). In earlier 

 chromatographic work (Hanks and others 1971; Hanks and Jorgensen 1973), we reported 

 evidence for and means of detecting some of these differences in subspecies of big 

 sagebrush (Artemisia tridentata subsp. tridentata and A. tvidentata subsp . vaseyana) . 

 In the course of this research, chromatographic analyses were done on other species in 

 the Tridentatae as well. This paper stresses some considerable differences discovered 

 among these species through chromatographic studies in 1969 and 1972, and outlines 

 phylogenetic relationships among these species as suggested by chromatographic patterns. 

 Other chromatographic analyses have been performed in the Tridentatae; however, this 

 study is much broader in scope and builds on earlier work. 



The large amount of genetic variation in natural populations of Artemisia provides 

 wide opportunity for the development of improved races through artificial selection 

 and breeding. Chromatography offers a rapid means of verifying the existence and 

 extent of hybridization and also a technique for identifying types that would satisfy 

 specific purposes. 



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