vi CONTENTS. 



THE ISOETACE^:, OR QUILLWORTS . . . 207 



KEY TO THE ISOETES 2l6 



THE AQUATIC QUILLWORTS 217 



THE AMPHIBIOUS QUILLWORTS . . . .231 

 THE TERRESTRIAL QUILLWORTS . . . . 247 

 CHECKLIST OF THE FERN ALLIES . . . .255 



GLOSSARY 267 



INDEX TO THE COMMON NAMES .... 274 

 INDEX TO THE SCIENTIFIC NAMES . . . 276 



