697 



may be regarded as casual, while in the present it is a constant cha- 

 racter of the plant. The ultimate branches are generally triangular, 

 each joint terminating in three long pointed teeth. 



THE SHADY EQUISETUM. 



Equisetum umbrosum, Willdenow. 

 Equisetum Drummondii, Hooker. 



" For this addition to the [British] species of Equisetum we are 

 indebted to Mr. Thomas Dmmmond, who found it on the banks of the 

 Isla and Esk, in Forfarshire, extending up the valleys almost to the 



