68 PLANTS OF YELLOWSTONE NATIONAL PARK 
Lepidium inconspicuuaiv has also been reported from the park. 
Awlwort ( Subularia aquatica) is a dwarf, stemless plant found 
growing in tufts in the shallow water or muddy shores of cold lakes, 
especially at the head of Yellowstone Lake. The small white flowers 
are usually submerged. 
Whitlowgrass {Drab a) .—The dr abas may be recognized by the short, 
flat pods, which are not notched and are several-seeded. The five 
species most commonly found in the park may be distinguished in 
the following manner: 
1. Flowers white- Drab a oligospermia. 
1. Flowers yellow. 2. 
2. Pods distinctly twisted._____ Draba streptocarpa. 
2. Pods not twisted. 3. 
3. Stems densely clustered, low________ Draba andina. 
3. Stems not densely clustered, taller. 4. 
4. Pods smooth-,- Draba nitida. 
4. Pods hairy_ Draba lapilutea. 
Figure 49.—Bee-flower. Reddish purple. Photograph by Dr. Harvey E. Stork. 
In addition to the above five species Draba kelleriana , D. crassi- 
folia , D. densifolia , D. nelsonii , and D. nemorosa have been reported 
as occurring in the park. 
Ilymenophysa pubescens has been introduced in recent years. 
CAPER FAMILY (CAPPARIDACEAE) 
Most of the flowers of the caper family have 4 sepals, 4 petals, and 
6 stamens like the mustard family, but the stamens are all of the 
