POLYGONACEAE (BUCKWHEAT FAMILY) 93 
so that they will be starved of the food assimilated by the leaves. 
Or when the ground is very soft the roots may be removed entire, 
by prying with a spade set into the ground vertically by the side 
of the root and pulling hard at the same time with the other hand. 
The roots of all three of the immigrant Docks here described are 
used in medicine; and the United States annually imports more 
than a hundred thousand pounds to supply the drug trade, at a 
cost of about ahalf-million dollars. If properly cleaned, split length- 
wise, and dried, they might be made to pay for the labor of their 
extraction from the soil. 
WILLOW-LEAVED DOCK 
Riumex mexicanus, Meisn. 
Native. Perennial. Propagates by seeds. 
Time of bloom: May to September. 
Seed-time: July to November. 
Range: Labrador to British Columbia, southward to Maine, Michi- 
gan, and Minnesota, and along the Rocky Mountains to central 
Mexico. 
Habitat: Moist, rich soil; fields, low meadows, waste places. 
This weed is tolerant of soil which is somewhat brackish and 
it often damages the hay crop from the salt-marsh meadows 
along the Coast. It has also made its way to Europe, where it 
is regarded with much dislike. 
Taproot rather stout, penetrating the soil to a great depth. 
Stems tufted, slender, ascending, flexuous, grooved, smooth, and 
pale green, one to three feet tall, usually simple. Leaves narrow, 
lance-shaped, pointed at both ends, the sides often nearly folded 
together; petioles rather short. Racemes erect, the whorls very 
dense; pedicels scarcely exceeding the calyx-lobes, jointed near 
the base; calyx olive to reddish brown, the valves triangular- 
ovate, delicately veined, all tubercled. Achenes dark red, smooth 
and shining; frequently an impurity of clover and alfalfa seed, so 
extending the range of a most troublesome weed. 
Means of control the same as for Rumex crispus. In well-tilled 
ground none of these large, deep-rooted weeds attain sufficient size 
to be very troublesome. 
