BRITISH FERNS. 5 



A SYNOPTICAL TABLE 



OF THE 



GENERA OF FERNS, AS FOUND IN THE WORKS OF BRITISH 



AUTHORS. 



FILICES ANNULATE. 



The thecae are provided with an elastic marginal ring, hythe operation of which the 

 cups containing the seeds are torn asunder, and the seeds dispersed. 



SECTION I. FILICES ANNULATE VEIUE. Thecae attached in masses to the back of 

 the frond. 



FAMILY I. Adiantacea. Thecae covered by a marginal or submarginal, prolonged 

 or elongate portion of the frond, or its superior cuticle : in some 

 instances having the appearance of an indusium, in others being 

 evidently a portion of the frond. 



ADIANTUM (Smith). The margin of the frond itself reflexed, and the 

 reflexed portion bearing nearly circular masses of thecae. British 

 Species, 1. CAPILLUS VENERIS ; Exotic species, very numerous. 



Blechnum (Smith). Thecae attached in a continuous line parallel to each side 

 'of the midvein; the line of thecae is covered by a continuous 

 indusium, from the back of which lateral veins issue, and extend 

 in parallel lines to the margin. Exotic species, 1. Lanceola ; 

 2. Trifoliatum; 3. Unilaterale, and about forty others. 



LOMARIA (Loudon) Thecae and indusium continuous and linear, as in 

 Blechnum, but either marginal or submarginal, no lateral veins 

 extending beyond the indusium to the margin. British species, 

 1. SPICANT. 



Stegania (Gray). Apparently identical with Lomaria. Exotic species, 

 1. Pater soni; 2. Lanceolata ; 3. Fluviatilis, and several others. 



PTERIS (Smith). Thecae in a continuous marginal line, covered by a 

 continuous marginal indusium. British species, 1. AQUILINA. 

 Exotic species, ninety-four. 



FAMILY ll.Polypodiace<z. Thecae in a circular mass, uncovered by any indusium. 



ALLOSORUS (Loudon). Margin of the frond convolute, concealing the 

 masses of thecae. British species, 1. CRISPUS. Exotic species, 

 few in number. 



