lower elevations upon gumbo-clay soils, usually on gentle slopes or 

 sometimes on ridges. Parry aster has a large woody taproot more 

 or less branched at the surface of the ground. From these woody 

 root crowns spring a number of leafy, woolly-hairy stems about 4 

 to 6 inches high which produce, usually during June, several daisy- 

 like flower heads. The white, petallike ray flowers are about three- 

 eighths of an inch long, and the narrow, spatula-shaped, hairy, alter- 

 nate leaves are about 1 to 2 inches long. Parry aster has caused 

 very heavy sheep losses in Wyoming, chiefly during the spring and 

 early summer. Probably losses are greater during that period be- 

 cause the mature plants contain much less of the toxic principle 

 and are less attractive to grazing animals. Apparently only a small 

 amount of Parry aster is required to produce fatal results in sheep, 

 but ordinarily this plant is not grazed except under conditions of 

 extreme hunger or when there is a shortage of other forage. The 

 toxic principle of Parry aster has been isolated, but its exact nature 

 has not been determined. 2 There are no known medicinal remedies. 

 Some observations indicate that Parry aster, which frequently occurs 

 on selenium-bearing soils, may absorb enough of this element to be 

 toxic to cattle. 3 



Asters belong to the immense aster, or composite family (Asteraceae, or 

 Compositae). The flowers are small and borne in dense clusters, or heads, 

 having the appearance of a single flower and commonly are produced from 

 late July to late September. Flowers are of two kinds: (1) Those in the 

 center of the heads (disk flowers), with yellow, tubular corollas which often 

 turn reddish or purplish in drying, and (2) those at the edge of the heads (ray 

 flowers) with strap-shaped and petallike, white, pink, blue, or purple corollas. 

 The ray flowers are usually in one row, not very numerous, and their corollas 

 are comparatively broad. The enlarged end of the stalk (receptacle), which 

 bears the flowers, is flat. Heads are normally borne on leafy stalks and are sur- 

 rounded at the base by several rows of strongly graduated, overlapping, some- 

 what herbaceous bracts. Numerous slender, white or tawny bristles are borne 

 on top of each "seed" (achene) in both the disk and the ray flowers. The leaves 

 are alternate, with entire or toothed margins. 



The most common plants with which the asters are likely to be confused 

 are the wild-daisies (Erigeron spp.). However, wild-daisy heads are usually 

 fewer (often one to three) and generally borne on partially leafless stalks, 

 the ray flowers are slender and generally numerous, and the disk flowers do 

 not noticeably change color in drying. Furthermore, the involucral bracts 

 are in fewer (mostly one or two) rows, usually looser, but slightly overlapping, 

 and are nearly equal in length. 



Asters are often grown as ornamentals, and a large number of well-recog- 

 nized species and horticultural varieties are now available through commercial 

 nurserymen. At least three of these species are native to the West. Rock 

 aster (A. alpinus), an alpine species ranging from Alaska to Colorado and 

 occurring in Europe and Asia, is a rather low plant with single stems arising 

 from a somewhat woody root crown. Under natural conditions the ray 

 flowers are white. This species, one of the hardy asters of nurserymen, is 

 especially suitable for rock gardens, and about 17 named horticultural varieties 

 of it have been developed. Smooth aster (A. laevis), a late blooming species 

 with blue ray flowers and a stout, smooth stem often covered with a bluish 

 waxy substance (glaucous), is native in the Rocky Mountains from British 

 Columbia to New Mexico and eastward to Ontario, Maine, and Georgia. 

 Wreath aster (A. multiflorus) , a rather low, much-branched species with 

 white ray flowers, occurs naturally east of the Rocky Mountains. 



2 Beath, O. A. CHEMICAL AND PHARMACOLOGICAL, EXAMINATION OP TUB WOODY ASTER. 

 Wyo. Agr. Expt. Sta. Bull. 123 : [40]-66, illus. 1920. 



"Hill, J. A. [REPORT OF THE] CHEMISTRY DEPARTMENT. Wyo. Aer. Expt. Sta Kept. 

 43 : 14-16. 1933. 



