viii HOW TO KNOW THE FERNS 



PAGE 



THE SORI ON THE BACK OF A HARTSTONGUE FROND 83 

 THE COMMON POLYPODY . . . .87 



ENLARGEMENT OF THE SORI ON THE FROND OF 



COMMON POLYPODY . . . .88 



THE BEECH FERN . . . . .89 



THE ROYAL FERN . . . . 94 



THE ADDER'S TONGUE . . . -97 



THE MOONWORT . . . . .99 



THE COMMON CLUB Moss .... 102 

 THE FIR CLUB Moss .... 104 



THE QUILLWORT ..... 108 

 AZOLLA CAROLINIANA . . . . IIO 



BARREN STEM OF EQUISETUM ARVENSE . .113 



FERTILE CONES OF EQUISETUM MAXIMUM . . 115 



THE DUTCH RUSH 120 



