MUSTARD FAMILY CRUCIFERAE 
TRUE WATER CRESS 
Radicula Nasturtium-aquaticum (L.) Britten & Rendle 
_ It frequently happens that when a plant is introduced 
into a new country whose climate is agreeable it finds 
conditions for growth and reproduction unusually favor- 
able, partly because it is freed from com- 
petition with many of its natural enemies. 
Under such circumstances many plants 
become pernicious weeds. 
This Water Cress could hardly be 
called a weed but it is an introduced plant 
which has spread over most of the central 
part of the continent and is 
common in most places. It 
is a native of Europe and 
northern Asia, and is now 
found in the West Indies 
and South America as well. 
It is greatly prized and ex- 
tensively used as a salad, 
for which purpose it was 
originally cultivated. 
3 True Water Cress grows in the water 
of |brooks and streams and forms very 
dense patches of considerable size. The 
smooth stems float on the water or creep on the mud, branching 
freely and rooting at the nodes. Leaflets of the pinnately com- 
pound leaves are 3-11, obtuse, ovate or oval, or the larger 
terminal one somewhat circular. 
The small white flowers have the usual structure of flowers 
of this family, and the petals are about twice as long as the 
sepals. The pods, turned upward from the slender pedicels of 
equal length, are divided longitudinally into 2 parts, each of 
which contains 2 rows of seeds. 
The Marsh Cress or Yellow Swamp Cress, Radicula palustris (L.) 
Moench, is common in wet places or shallow water. The smooth 
erect stem is 8-32 inches high and much branched. Leaves are 
pinnately cleft or more deeply parted; the upper may be deeply 
narrow lobed. The small orange-yellow flowers are on pedicels as 
short as the flower but longer than the ellipsoid-cylindric pods. The 
blooming season is May to August. 
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