145 



II.-FEKN ALLIES. 



Azolla, Lam. 



A. caroliniana, Willd. Tropical and subtropical 

 America. 



A. pinnata, R. Br. Australia. 

 Bernhardia. See Psilotum. 



Equisetum, L. 



E. arvense, L. North temperate and Arctic regions. 

 Hook. Brit. Ferns, t. 60. 



E. fluviatile, L. See limosum. 



E. hyemale, L. North temperate and Arctic regions. 

 Hook. Brit. Ferns, t. 64. 



E. limosum, L. North temperate and Arctic regions. 

 Hook. Brit. Ferns, t. 62. 



E. maximum, Lam. North temperate regions. 



E. ramosissimum, Desf. Warm temperate and tropical 

 regions. 



E. robustum, A. Br. North and central America. 



E. scirpoides, Michx. North temperate and Arctic 

 regions, 



Isoetes, L. 



I. lacustris, L. Europe and North America. Hook. 

 Brit. Ferns, t. 55. 



I. malivernianum, Cesati & De Not. ]taly. 



