124 FERNS OP GREAT BRITAIN. 



19. Ophioglossum (Adders-tongue). 



1. 0. vulgdtum (Common Adder's-tongue). — Barren 

 frond egg-shaped, blunt ; fertile frond club-sliaped. This 

 is a common plant, abundant in many parts of Eng- 

 land, and easily known from any other fern. One 

 who was not a botanist would describe its fuU-grown 

 frond as being a green leaf, sending up from its base 

 a stalk bearing a spike. If we look for this plant in 

 May, we may find the bud underground: this was 

 formed in the previous autumn, and on being opened, 

 it may be seen to enclose not only the leaf and spike 

 for the next year, but also the rudiment of the leaf for 

 the year after. The plant, when seen in the middle of 

 the month of June, at which time it is fully developed, 

 is erect, with a long smooth succulent stem, of a pale 

 green colour, a leaf of a deeper green tint, not with 

 forked veins like most ferns, but with veins forming 

 a net-work, while from the inner part of the leaf rises 

 the stalk, which varies from about an inch to three inches 

 in length. The spike on this stalk tapers towards the 

 summit, and is formed of two lines of crowded capsules 

 imbedded in its substance, and occupying its two opposite 

 sides. The capsules, which are globose, are filled with 

 a fine dust, like the pollen of flowers. When fuUy ripened 

 they discharge their contents, and if the soil is moist the 

 plant becomes so plentiful in the pastures in the course 

 of a few summers as to injure it greatly. Though local 

 in distribution, yet in parks and clayey pastures we 

 might sometimes gather a basket full of plants in the 

 course of a few hours. It is no marvel that our fore- 



