132 
PLANTS OF YELLOWSTONE NATIONAL PARK 
the akenes, and consists of 5 to 10 transparent scales the midribs of 
which are prolonged to form awnlike tips. The akenes are covered 
with long hairs. 
Yarrow {Achillea lanulosa) is common throughout the Northern 
Hemisphere and has a strong and characteristic odor. In fact, the 
plant can be recognized by its odor alone after one has become famil¬ 
iar with it. It grows 8 inches to 2 feet high and has alternate 
leaves that are twice pinnately dissected into very small and narrow 
divisions. The heads are relatively small and contain few ray 
flowers and a somewhat larger 
number of disk flowers, both 
white. The bracts of the in¬ 
volucre are whitish with a 
greenish center. The akenes 
are linear or oblong and there 
is no pappus. 
Figure 109. —Gaillardia. Yellow. Photo¬ 
graph by A. R. Sweetser. 
Figure 110.—Big sagebrush. Yellowish 
white. Copyright, J. E. Haynes. 
Oxeye daisy {Chrysanthemum leucanthemum ).—This is a Euro¬ 
pean plant which has become naturalized in the United States and is 
very common in many places in the East. It is not common in the 
park, but is occasionally found. It is a smooth herb, 1 to 2 feet high, 
with toothed or pinnately lobed leaves which are spatula-shaped, 
but become smaller and narrower higher up on the stem. Most of 
