Water-cress 



119 



seeds, which may be scattered along cool brooks, and by 

 bits of the stems planted in the earth. In order that it 

 may reach its best development, the water should be pure, 

 cool, and clean. When once established in a permanent 

 place, it will persist indefinitely, taking care of itself. 

 AVhen a natural brook is not to be had, it may be grown 

 in a moist shady place in the garden where it may be 

 watered frequently. Sometimes it is grown in the pit of 

 an abandoned hotbed, into which water may be run with 

 a hose. If the ground is kept moist, or even wet, the 

 plant will thrive and it will not be necessary to have it 

 covered with water. The plant is best grown, however, by 

 being colonized along brooksides and about springs. If 

 the colonies are picked or harvested very closely, the plants 

 will suffer. 



Watek-cress sowbug (MancaseUus hrachyurus) . — A gray- 

 ish aquatic species of sowbug more or less shrimp-like in form 

 that attacks the submerged portions of the plants, cutting the 

 roots and stems. Control: There is no practicable method of 

 controlling sowbugs in natural streams and ponds. Some groovers, 

 however, have been able to overcome the difficulty by growing 

 the plants in broad shallow beds sloping towards the center, 

 where a trough ten inches square lined with boards extends 

 the whole length of the bed. When the sowbugs become 

 abundant, the water is shut off for twelve to twenty-four 

 hours, allowing the beds to drain. Water is retained in the 

 trough, in which the sowbugs soon accumulate in great num- 

 bers. They may be destroyed by the addition of a liberal 

 quantity of copper sulfate solution. Less injury will result 

 if water is drained off soon after the cress has oeen gathered. 



For our purpose we may use for water-cress the botanical 

 name Roripa Nasturtium-oquaticnm, Hayek. (Sisumhrium Nas- 

 turtium-aquaticum, Linn.). Thereby we come upon the most 



