10 



Methods of Reproduction and Spread. 



The plant produces a great amount of seed which is carried by the 

 irrigation water to new fields and ditches. Small plants are sometimes 

 washed out and carried to a distance by the water, but it is the seed 

 falling on the water which is the important means of spread. 



The seedlings do not bloom nor produce seeds the first year; and 

 it may take the plant several seasons to develop a tuber large enough to 

 send up a flowering stem. The young plants do not produce an erect 

 stem, but only a bunch of leaves. Each year the old tuber dies in the 

 fall; but before this happens it has given rise to one or more new 

 tubers which live through the winter and begin growth again very 

 early the next spring. When more than one new tuber is formed, this 



Figure 6. Roots and Early Spring Growth of the Poison Parsnip 

 (Water Hemlock). Both the rootstock and the fleshy roots contain 

 the deadly cicutoxin. 



results in a local increase in the number of plants. For this reason the 

 poison parsnip plants often grow in clusters which all originated from 

 a single seed. 



When the new tuber is first formed it contains little or no cicutoxin, 

 but as it grows older the amount increases until it becomes as poisonous 

 as the old ones. This difference between the new tubers and the old is 

 probably what has led some writers to conclude that the plant is less 

 poisonous at certain times in the year. The old decaying tubers retain 

 most of their cicutoxin, the poisonous principle, and are still poisonous 

 when almost completely decayed. 



