SECT. I. CONSERVATIVE ORGANS. 1Q7 



If a frond of this Brake is taken and pulled up with 

 the hand, the lower extremity which is black and 

 discoloured by having been partly sunk in the 

 earth, and to which some small fibres are occasion- 

 ally attached, is apt to be mistaken for the root, 

 and has, I presume, been often mistaken for it. 

 But the real root from which the frond has been 

 thus detached still remains in the soil, extending 

 itself in a horizontal direction, at the depth of from 

 three to four inches below the surface, sometimes 

 simple and sometimes branched, but always fur- 

 nished with lateral fibres. Its thickness is about 

 that of the lower part of the frond, the surface 

 being of a dark and dusky colour partly covered 

 with a velvety sort of down, and the frond issuing 

 from it sometimes in clusters, but generally at con- 

 siderable intervals. To what length an individual 

 root may thus extend itself I have not yet been 

 able to ascertain ; but I have often taken up por- 

 tions of root measuring from eighteen to twenty 

 inches. 



The Trunk. In some Ferns the trunk is a cylin- Modifi- 

 drical and upright stem ; composed as it were of C 

 several tubes inserted into one another by the ex- 

 tremities, the insertions forming knots or joints, as 

 in those of the straw of the Grasses ; sometimes 

 simple and sometimes branched, as in the genus 

 Equisetum. In others the trunk, which is also a 

 jointed stem, is weak and trailing, striking root at 

 the joints, as in Pilularia. In the genus Lycopodium 



