216 



HALORAGACE^l. 



HiPPtJRis vuLGARis (Common Mare's tail). 



confounded with the genus Equisetum (Horse-tail), a 

 plant allied to the Ferns, which also has a jointed stem 

 and rigid leaves, but bears its fructification in terminal 

 spikes, or heads. El. June, July. Perennial. 



2. MYRIOPHYLLUM ( Water Milfoil). 



1. M. spicdtum (Spiked Water Milfoil). Flowers in 

 whorls, forming a slender leafless spike. Stagnant 



