OSMUNDA. 139 



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 are, therefore, con- 

 sidered as being produced on the margins of a contracted 

 frond. "When mature, the margin splits across at intervals 

 corresponding with the centre of each spore-case, so that 

 eventually the spike resembles a double row of gaping 

 spherical cavities. 



The Adder' s-tongue is very abundant in the localities 

 where it is found, which are damp meadows and pastures, 

 on a loamy soil. It is generally distributed over England, 

 but is less abundant in Wales, and the other parts of the 

 United Kingdom. The species is a common European 

 plant, and is found in North America as well as in Africa. 



There is no difficulty in cultivating the Adders-tongue, 

 whether in pots, or among an out-door collection of Ferns ; 

 the essentials are a stiff loamy soil, and the constant pre- 

 sence of water enough to prevent drought. 



Genus XYI. OSMUNDA, Linnaus. 

 THE Osmunda is called the Eoyal Fern, and well it deserves 



