130 
PLANTS OP YELLOWSTONE NATIONAL PARK 
is often more than a foot long. The flowering stems become about a 
foot high. The ray flowers are 1 or 2 inches long. 
Balsamorrhiza incana is densely white-hairy all over and the 
leaves are pinnately lobed. 
White mule-ears (Wyethia helian- 
thoides).— The hairy stems of this 
species are 8 to 16 inches high and 
unbranched, and each one usually 
bears a single, large head with yel¬ 
low disk flowers and white ray 
flowers. The leaves are alternate, 
oval or lance-shaped, entire or 
nearly so ? 4 to 8 inches long, and 
most of them are narrowed into a 
short, margined petiole. The heads 
are about an inch high, and the 
narrow, leaflike bracts of the invo¬ 
lucre are numerous. Each flower 
is partly enclosed by a chaffy bract 
about as long as the flower. The 
ray flowers are nearly 2 inches long. 
Common sunflower (Helmuthus an¬ 
num). —This is the plant from 
which the large, cultivated sun¬ 
flower originated. The hairy stems 
are 3 to 6 feet tall and more or 
Copy- less branched, and the leaves are 
mostly alternate with blades broadly 
ovate, 3 to 12 inches long, and toothed. The heads are large 
and conspicuous, the disks 1 or 2 inches broad, and the rays usually 
more than an inch long. The ray flowers are brownish or purple. 
Helianthus nuttallii usu¬ 
ally grows about 3 feet high 
and the lowermost leaves are 
opposite, but the others are 
alternate. They are lance- 
shaped and vary from 3 
to 6 inches long. The ray 
flowers and the disk flowers 
are yellowish brown. 
Prairie sunflower (Helian¬ 
thus scaberrimus) , which 
has very firm, thick, rough 
leaves, has been reported as 
npcurrinfr in the nark FlGUKE 108 -“ 1Sunflower - Yellow. Photograph by 
occurring in ine parn. Dr Harvey E st0r k. 
Figure 107. —Sunflower. Yellow, 
right, J. E. Haynes. 
