208 HISTORY OF BRITISH FERNS. 



derived from the Greek opMs, ophios, a serpent, and glossa, 

 a tongue ; and is applied in consequence of the resemblance 

 of the fertile fronds to the tongue of a serpent. 



Ophioglossum vnlgatum, Linnwus. 



The Common Adders-tongue. (Plate XVIII. fig. 8.) 



A small stemless plant, producing a few coarse brittle 

 roots from a central crown which represents the stem, and 

 which annually produces a bud from which the new frond 

 arises. The young fronds are produced about May, and 

 perish by the end of the summer. They grow from six 

 inches to ten or twelve inches in height, with a smooth, 

 round, hollow, succulent stipes of variable length. In the 

 upper part this becomes divided into two branches, the one 

 branch leafy, entire, smooth, ovate-obtuse, traversed by 

 irregularly anastomosing veins, forming elongated meshes 

 within which are free divaricating veinlets. The fertile 

 branch is erect, contracted about half its length, being 

 soriferous, forming a linear slightly tapering spike, which 

 consists of two lines of crowded spore-cases imbedded in 

 the substance of the spike, and occupying its two opposite 

 sides. The spore-cases arc, therefore, considered as being 

 produced on the margins of a contracted frond. When 



