132 



NATURAL ORDERS, GENERA AND SPECIES. 



Order Hydropterideae. 



Tribe MARSILEACE^, 100 

 PILULARIA globulifera, 100 



Order Equisetaceae. 

 EQUISETUM arvense, 106 ; pra- 

 tense, 108 ; maximum, 109 ; 

 sylvaticum, III; palustre, 112; 

 limosum, 114; hyemale, 115; 

 variegatum, 117 



Order Lycopodiaceae. 

 LYCOPODIUM clavatum, 120; 

 annotinum, 122 ; alpinum, 123 ; 

 inundatum, 124; selago, 125 



Order Selaginellaceae. 

 SELAGINELLA selaginoides, 127 

 ISOETES lacustris, 129 ; hystrix, 

 130 



