SECT. vm. OPHIOGLOSSACE&. 365 



as a perfume in the Sandwich Islands, and its rhizome 

 serves for food, as that of the Marattia salicina does in 

 New Zealand. 



The OPHIOGLOSSACE^E, or Adder's Tongue ferns, are 

 few in number, and present comparatively little differ- 

 ence in structure. They are known among the exannu- 

 late series, from the Marattiacese, by having their fertile 

 fronds contracted, bearing their sporangia at the mar- 

 gin, so that being entirely occupied by sporangia, the 

 fertile fronds appear as if they were an inflorescence 

 distinct from the foliaceous organs, as indeed they are 

 analogically. In this group there is the further differ- 

 ence that the fronds are not circinate, but straight, in 

 their aestivation. 



These Adder's Tongue ferns are dwarf herbaceous 

 plants, differing greatly in structure from the true 

 ferns, though there is some similarity to them in the 

 fructification. They are divided into four genera, of 

 which Ophioglossum and Botrychium are best known. 

 The base of the stem is thick and bulbiform, and sends 

 off spreading succulent roots. The species of the genus 

 Ophioglossum are chiefly plants of a warm climate, but 

 Ophioglossum vulgatum, or common Adder's Tongue, 

 is distributed in almost every part of the globe. In 

 England it is exceedingly abundant in meadows and 

 pastures, and varies in height from a few inches to a 

 foot, in moist soil. It has one barren ovate and one 

 fertile linear frond. The barren frond, which is of a 

 yellowish-green colour, invests the stem of the fertile 

 frond like a spathe ; its form is ovate, varying to ovate 

 lanceolate, and more or less obtuse, with a complicated 

 network of anastomosing veins. Bivalved sporangia 

 form two parallel series on the margins of the club-like 

 terminations of the fertile frond. Soon after the fruit 



