List of Illustrations. 



COMMON SCOURING-RUSH. Equisetum hieinale. (In colours.) . Frontispiece. 



PAGE 



SECTION OF SCOURING-RUSH STEM 12 



JOINT OF SCOURING-RUSH STEM 13 



SPORE-CASES 13 



SPORES, ENLARGED 14 



CROSS SECTION OF STEM OF COMMON SCOURING-RUSH .... 19 



YOUNG STEMS OF COMMON SCOURING RUSH 20 



FERTILE STEM OF COMMON SCOURING RUSH. Equisetum hieinale . 22 



SHEATH OF GREAT SCOURING-RUSH. Equisetum robustum ... 26 



EQUISETUM FERRISSI, SECTION OF STEM 28 



EQUISETUM FERRISSI, TIP OF STEM .... 3 



SMOOTH SCOURING-RUSH. Equisetum la-vigatuvi .... facing 30 



SHEATH OF SMOOTH SCOURING-RUSH 32 



CATKIN OF SMOOTH SCOURING-RUSH 32 



BRANCHED EQUISETUM. Equisetum Funstoni facing 34 



SHEATH OF EQUISETUM FUNSTONI 34 



CATKIN OF EQUISETUM FUNSTONI . 35 



SHEATH OF VARIEGATED SCOURING-RUSH 36 



VARIEGATED SCOURING RUSH. Equisetum variegatum , . . facing 36 



CATKIN OF VARIEGATED SCOURING-RUSH. 37 



SECTION OF VARIEGATED SCOURING-RUSH STEM 38 



DWARF SCOURING-RUSH. Equisetum scirfioides facing 38 



SHEATH OF DWARF SCOURING-RUSH ........ 39 



CATKIN OF DWARF SCOURING-RUSH 40 



STERILE FROND OF FIELD HORSETAIL. Equisetum arvense . . facing 44 



FERTILE FROND OF FIELD HORSETAIL facing 44 



SECTION OF FIELD HORSETAIL STEM 46 



WOOD HORSETAIL. Equisetum silvatic urn. (In colours) . . . facing 46 



EQUISETUM ARVENSE DECUMBENS facing 48 



EQUISETUM ARVENSE CAMPESTRE facing 48 



BUDS AND TUBERS OF FIELD HORSETAIL .....'. 49 



FERTILE FROND OF IVORY HORSETAIL. Equisetum telmateia . . facing 50 



SECTION OF STERILE FROND OF IVORY HORSETAIL .... facing 52 



STERILE FROND OF SHADE HORSETAIL. Equisetum pratense . . facing 54 



FERTILE FROND OF SHADE HORSETAIL facing 54 



STERILE FROND OFWOOD HORSETAIL. F.qiiisctum silvaticum . facing 56 



FERTILE FROND OF WOOD HORSETAIL facing 56 



BUDS AND TUBERS OF WOOD HORSETAIL 57 



