THE GENUS EQUISETUM 

 believe that the species once had an even wider range than it shows at present. All these 

 facts indicate a high degree of antiquity for the living species of Equisetum, quite apart 

 from the fossil record of the genus. 



All the European species have been available to me for study of both mitosis and 

 meiosis. In addition, a very large Horsetail with sparsely branched shoots as thick as 

 one's finger and reaching 15 ft. in height was sent to me from Glasnevin Botanic Garden 



Fig. 211. Silhouette of a live plant o( Equisetum scirpoides Michx. grown in cultivation 



but originally from Norway. Natural size. 



in Dublin, and subsequently identified by Mr Alston of the British Museum as the North 

 American species E. robustum A.Br. It proved easy to cultivate and in time bore cones. 

 Lastly, sterile and fertile material of three other forms, not strictly speaking species 

 although frequently treated as such in Floras, have been examined. These forms are 

 E. trachyodon A.Br., E. Moorei Newman and E. litorale Kuhlw., and they will be dealt with 

 separately at the end of the chapter. 



21 1 



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