OPHIOGLOSSUM. 
209 
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 Adders-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 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 
presence of water enough to prevent drought. 
Ophioglossum lusitanicum, Linnceus. 
The Dwarf Adders-tongue. (Plate XXI. fig. 3.) 
This species of Adders-tongue is technically distin¬ 
guished by the small lanceolate and somewhat fleshy barren 
branch of its fronds, and by its being altogether much 
smaller than the common species. It may, indeed, be at 
once known from that by this difference of size, as well as 
by its difference of form. The stem forms a short oblong 
p 
