LIST OF ILLUSTRATIONS, ix 



PAGE, 



SELAGINELLA CINERASCENS facing 146 



OREGON SELAGINELLA. Selaginella Oregana facing 148 



PRICKLY MOUNTAIN MOSS, ^laginclla s/>hui.<a . . . facing 150 



CREEPING SELAGINELLA. Selaginella aj>us ....... 156 



SPIKE OF CREEPING SELAGINELLA 157 



SELAGINELLA LUDOVICIANA facing 158 



SELAGINELLA LUDOVICIANA. (In colours) facing 160 



SELAGINELLA DOUGLASII ..." 160 



RESURRECTION MOSS. Selaginella !ej>ido/>hyUa . .... facing 162 

 BRANCH OF THE RESURRECTION MOSS ..-. 162 



RESURRECTION MOSS, WHEN DRY . . . facing 164 



SPOROCARPS OF AZOLLA 171 



SALVINIA NATANS 176 



CROSS-SECTION OF SALVINIA SPOROCARPS 171 



SPOROCARPS OF SALVINIA NATANS 176 



WATER FERN. Azolla Caroliniana . 182 



THE HOME OF AZOLLA facing 182 



AZOLLA FILICULOIDES 184 



SPOROCARP AND SPORANGIA OF MARSILIA ' . 187 



VEINING IN THE LEAF OF MARSILIA . 188 



SPOROCARP OF MARSILIA 188 



CROSS-SECTION OF PILULARIA SPOROCARP 189 



MARSILIA QUADRIFOLIA. ( In colours) facing i,;6 



MARSILIA QUADRIFOLIA ~ facing 198 



MARSILIA UNCINATA . facing 198 



MARSILIA VESTITA facing 200 



MARSILIA MACROPODA . facing 202 



PILULARIA AMERICANA facing 206 



LEAF OF ISOETES SHOWING SPORANGIUM ....... 211 



CROSS-SECTION OF ISOETES LEAF ... ..... 211 



MEGASPORES OF ISOETES ... ....... 213 



MICROSPORES OF ISOETES 214 



BRAUN'S QUILLWORT. Isoetes echinosfiora Braunii .... facing 220 



MEGASPORE OF BRAUN'S QUILLWORT 220 



MEGASPORE OF ISOETES ECHINOSPORA MURICATA 221 



MEGASPORE OF ISOETES TRUNCATA 222 



MEGASPORE OF ISOETES ECHINOSPORA FLETTII -.,... 222 



MEGASPORE OF ISOETES LACUSTRIS 224 



MEGASPORE OF TUCKERMAN'S QUILLWORT. Isoetes Titckcnnani . . 225 



MEGASPORE OF BOLANDER'S QUILLWORT. Isoeies Bo/andcri ... 228 



MEGASPORE OF ISOETES HIEROGLYPHICA ....... 229 



MEGASPORE OF ISOETES MACOUNI 229 



ENGELMANN'S QUILLWORT. Isoetes Engclinanni facing 234 



MEGASPORE OF ENGELMANN'S QUILLWORT 234 



MEGASPORE OF ISOETES ENGELMANNI CAROLINIAIMA 235 



MEGASPORE OF EATON'S QUILLWORT. Isoetes valida 236 



MEGASPORE OF DODGE'S QUILLWORT. Isoetes Canadensis . . . . 238 



MEGASPORE OF RIVER-BANK QUILLWORT. Isoetes ripar ia .... 239 



MEGASPORE OF ISOETES SACCHARATA . 2 4 c 



