100 GENUS AETEMISIA. 



behavior. Heterophylla is the characteristic form in the bunch-grass prairies of Cali- 

 fornia and Oregon, where it makes societies Hke those of gnaphalodes. In California 

 especially it has largely disappeared with the native grasses, and is now found chiefly 

 in the low savannah formed by the coast sagebrush. In Washington and British Colum- 

 bia heterophylla is largely replaced by tilesi, which takes a similar role in the grassland. 



In addition to the dominant grasses of the respective associations, these forms mix and 

 alternate with a large number of subdominant herbs, especially the asters, goldenrods, 

 sunflowers, and other species of the autumnal aspect. Gnaphalodes, ludoviciana, or 

 wrighti is frequently associated with one or more of the other grassland species of Arte- 

 misia, namely, dracunculus, campestris, and frigida. On the Pacific Coast heterophylla is 

 often found with A. calif ornica, and in the interior with A. tridentata. 



As indicators, all of the subspecies considered denote the climax association and cli- 

 mate, and hence are valuable in reconstructing grassland that has disappeared. This is 

 particularly true in California, where the deep-rooted heterophylla persists long after the 

 native bunch-grasses have been grazed out. In general, gnaphalodes and ludoviciana 

 indicate greater moisture, as they are most abundant in the moister true prairies and foot- 

 hills respectively. As a rule they are not good indicators of overgrazing and other dis- 

 turbance, probably owing to their lack of mobility, and are in corresponding contrast to 

 other grassland species, such as A. frigida and campestris. 



USES. 



This, the most abundant sagewort in western North America, forms an important part 

 of the late fall and winter feed for all classes of stock, but especially for sheep. It is 

 variously known on the ranges as sage-weed, white sage, and mugwort. The taste is so 

 pungent that it is scarcely touched until after frost, but late in the season, when other feed 

 is scarce, it is quite generally eaten. There seems to be no preference as to subspecies, 

 since all of the common ones, particularly discolor, ludoviciana, and gnaphalodes, are 

 reported upon favorably. It seems, therefore, that the inclusive name of Artemisia 

 vulgaris, or sagewort, is the only one with which the grazing experts need to concern 

 themselves when studying the value of these plants. 



The medicinal properties of Artemisia vulgaris have led to its use for a great variety of 

 diseases. This has been largely confined, however, to domestic practice, the plant being 

 scarcely more than noticed in the pharmacopoeias. The subspecies typica is employed in 

 Europe as an emmenagogue and for epilepsy and colds. In California subspecies hetero- 

 phylla is used by the Indians as a remedy for colds, headache, fevers, stomach troubles, 

 and rheumatism. The methods employed are described by Chesnut (Contr. U. S. 

 Nat. Herb. 7:392, 1902). In France, typical vulgaris has been worked up into moxas, 

 which are burned for purposes of cauterization. Since its value for this purpose depends 

 chiefly upon the woolly tomentum, it seems that some of the more heavily tomentose 

 American subspecies, such as candicans or gnaphalodes, would be better adapted to the 

 purpose. The essential oils present have been studied by Rabak (Pharm. Rev. 24:324, 

 1906). By far the most important medical use of the plant is as a preventive of hay- 

 fever in those cases which are caused by its own pollen. Some hay-fever sufferers are 

 particularly sensitive to the pollen of this plant, as is indicated by skin-reaction tests. 

 Such people find relief by taking at first injections of very dilute pollen solution (about 

 1 : 300,000) and gradually increasing the strength until no reaction is obtained. This 

 desensitization enables the patient to pass through the hay-fever season without being 

 subject to attacks, assuming that he is not suffering from the effect of other pollens as 

 well. Preliminary studies indicate that the pollen of the different subspecies all react 

 alike. Therefore, in testing and treating hay-fever cases, the speciaUst need pay no 

 attention to the complicated series of subspecies and minor variations. (See further 

 under Atriplex rosea, p. 260.) 



