328 COMMON WEEDS 



Myriophyllum verticillatum L. (Fig. 93) is another 

 common species of Water Milfoil very closely resembling 

 the one already mentioned, but with stronger stems 

 and more leaves in a whorl. The flowering spike is 

 erect when in bud, that of M. alterniflorum being 

 curved at the tip. 



UMBELLIFER.E 



Many umbelliferous plants are inhabitants of wet 

 places, or grow in water at the sides of rivers and 

 ponds and in ditches. The following are often trouble- 

 some weeds in such situations : 



Marshwort (Apium nodiflorum Reich.) is a pest with 

 the habit of watercress, and sometimes found in water- 

 cress beds. The stem is procumbent, i to 3 feet, with 

 roots at the joints. The leaves are pinnate or trifoliate, 

 the leaflets being usually ovate with blunt irregular ser- 

 rations. The flowers are white, in umbels placed 

 opposite to the leaves, and open from July to August. 



Apium inundatum R. is an allied plant, which grows 

 generally in deeper water. It has creeping or floating 

 stems, and most of the leaves are submerged, with fine 

 linear segments. The leaves at the surface of the 

 water have pinnate, wedge-shaped leaflets. The flowers 

 and umbels are very small, appearing from June to 



July. 



Water Parsnip (Stum angustifolium L.) is a common 

 ditch plant, with creeping rootstock and erect round 

 stem, i to 3 feet high. The leaves are 4 to 8 inches 

 long, pinnate, the leaflets ovate and irregularly lobed. 

 The umbels of white flowers are lateral, opposite the 

 leaves, flowering taking place in August. 



