170 NATURE STUDY AND AGRICULTURE 
17. Green Foxtail: 
Pigeon Grass.—In some sections 
this is less common than the preceding, but in other localities 
it is even more abundant. It is easy to distinguish the two 
iG 
a. YELLOW FoxTAIL 
6. GREEN FOXTAIL 
species if they are brought together for 
comparison. 
The two foxtails generally reduce the 
yield of wheat more than all other weeds 
combined, and we may therefore, with 
good reason, call them our worst weeds. 
18. Barnyard Grass: Cockspur 
Grass. — This is often associated with 
| pigeon grass, though it is fond of richer 
ground such as it would find in the 
barnyard. The beginner will find it 
hard to distinguish from pigeon grass 
until it heads out. Then the blossoms 
appear in a dense panicle like that 
of Japanese millet. 
19. Old Witch Grass. — This is another annual grass, 
found wherever weeds grow. Until it heads out we distin- 
guish it from pigeon grass and 
barnyard grass by the hairy 
sheaths, — the lower part of the 
leaf that clasps the stem. The 
blossoms are on slender stems 
and in a very loose or open 
panicle. 
20. Wild Oats.— This is easy 
to identify, but sometimes the 
name is erroneously applied to 
of the prairie in sections where 
BARNYARD GRASS 
the native porcupine grass 
the real villain has not yet 
become familiar. The grain of wild oats has a ring of hairs 
