44 
PLANTS OF YELLOWSTONE NATIONAL PARK 
Ladiestresses (Spiranthes stricta ) resembles an orchid, but the 
white flowers are borne on the spike in three spirally arranged rows, 
giving the spike the appearance of being twisted. 
Figure 28.—White bog-orchid. White. 
■f Photograph by Dr. Harvey E. Stork. 
“ . i 
Figure 29. —Ophyrs. Greenish. Photo¬ 
graph by A. R. Sweetser. 
Ophyrs (Listera convallarioides ) 
has a slender stem 5 to 10 inches 
high, somewhat hairy but naked, 
except that there is a pair of oppo¬ 
site, rounded, or kidney-shaped 
leaves just below the flower cluster. 
The small greenish flowers are 
borne in a loose raceme. 
Listera nephrophylla is similar, 
but the stem is smooth. 
One-leaf hog orchid ( Lysiella ob- 
t us at a) is a small plant with a 
single, more or less oblong, leaf at 
the base and greenish-yellow flow¬ 
ers. The outer sepals are turned 
back as is also the lip. 
Figure 30. —Coralroot. Brownish purple. 
Photograph by A. R. Sweetser. 
Coralroot (Corallorhiza) .—The name, coralroot, is a misnomer, for 
the plant has no root at all but only an underground stem. It 
also has no “ leaf green ” or chlorophyll. Therefore, it cannot 
