WEED SEEDS V.8 FOOD. 19 
in itself to prevent practically all of the damage to grain crops by the 
homed larks. 
Finally, it may be said in the bird*- favor tliat at the worst the 
damage to grain from the horned lark is not great, and thai it is 
more than counterbalanced i>y the good done through the destruc- 
tion of harmful insects and the Beeds <>t' injurious weeds. 
\\'i ia». 
The plants commonly known as weeds, from their injurious effect 
upon agriculture, are more important than any of the other enemies 
of the farmer. They rob the Boil of it- nutritive elements and of its 
moisture, and thus reduce the size of crop-. They arc mostly hardy. 
vigorous plant-, and shade and choke out the more delicate plant- of cul- 
tivation. Many fungous diseases of cereal, fruit, and other crop-, such 
as ru-t- and rots, depend for their continuance upon weeds as interme- 
diate host-. Such weed- a- the mustards are especially well known as 
the primary hosts of rust-. Some weeds poison stock; the spiny seeds 
or burs of others Lessen the value of wool, besides being the cause of 
annoyance to all animal- on the farm and to man. In these and in a 
thousand other way- weed- injure the farmer. They are present 
everywhere, and their numbers are limited only by the capacity of the 
soil and the extentof available space. Passing to particular examples 
of their fecundity, we may mention that a single plant of foxtail 
(Plate II. fig. A), the seeds of which were eaten by nearly 350 of the 
horned larks examined, ha- been known to produce 113,000 seeds, and 
a plant of red root (tumbleweed), the seeds of which are the food next 
preferred, has produced 115,000 seeds. Such reproductive power- if 
unchecked would result -oon in covering the entire surface of the 
earth with weeds. Even a- it i-. the surface -oil contain- so many 
seeds that they often seem to constitute a considerable percentage o( 
its bulk. At Ames. Iowa, a square rod of ground in a garden, which 
had been in potatoes the year before and cultivated with a hoe. 
yielded L87,884 plants of eight common weeds. a Crab grass and its 
allies, which are great pests in permanent lawns, and the seeds ^\ 
which are eaten freely by the horned lark-, occur in even greater 
number. Professor Beal states that each square quarter of an inch in 
hi- garden in Maryland, when first cultivated in tin 1 spring, contained 
at least one plant of crab grass. Upon this basis tin 1 number oi' plant- 
to a square rod is 027,264. Three time- the weed- were cut off, but 
each time they appeared in a- great number- a- before. 
The above statements indicate the vast number- of weeds on farms, 
and -how that to prevent them from possessing the land they must be 
destroyed in all stages of growth. The damage they cause, reckoned 
"Hull, -tin No. re. Exp. Sta., la. State College, p. 465, L9< 
