36 THE SCOUR1NG-RUSHES. 



inch long and a third as broad. They are nearly ovate, 

 with a rounded apex, and the base is either included in 

 the uppermost sheath or raised above it on a short stem. 

 In most specimens there is a cup-shaped sheath of the 

 same colour as the catkin, closely appressed to the lowest 

 whorl of sporophylls. 



Equisetum Funstoni is a plant of the extreme South- 

 west. It is very abundant in southern California below 

 about 1,500 feet altitude, and prefers moist sand, espe- 

 cially along streams, although it occasionally grows in 

 soil so dry that the stems perish during the summer. In 

 general appearance the species is so much like Equisetum 

 lavigatum that it is easily mistaken for it. Four ecologi- 

 cal forms have been named. It is interesting in this 

 connection to note that there are but two other species 

 of Equisetum in the world, named for botanists. 



The Variegated Scour ing-Rush. 



One familiar with the appearance of the smooth 

 scou ring-rush might easily mistake the variegated 

 scouring-rush (Equisetum variegatuiti) for a small 

 form of that species. Superficially they are much 

 alike except in size and the markings of the 

 sheaths, but a close examination will show many 

 other points of difference. Equisetum variega- 

 tum is much the more widely distributed, and 

 in America the habitats of the two do not 

 overlap to any great extent. 



The stems of this species grow in tufts from 

 the apex of the root stock, and reach a height of 

 sheath of from six to twenty inches. They are slender, 

 a"i l ^ifjun. barely an eighth of an inch in diameter, and so 



