88 



HORSETAILS AND CLUB MOSSES 



The fertile stems of Equisetum arvense literally cover the 

 ground in May. These fertile stems develop like the sterile 

 stems from the rhizomes. The stems are not branched but 



FIG. 48. Equisetum arvense. The upper left figure is the strobilus; the 

 upper right figure is a longitudinal section, the stalked sporophylls with 

 sporangia showing clearly. The lower left figure is a cross-section of the 

 strobilus viewed from the underside; the lower right figure is a cross-section 

 of the strobilus viewed from above. 



they are clearly differentiated into nodes and internodes. 

 The internodes are pink, furrowed and free of chlorophyll, 

 the nodes have sheaths with from eight to twelve brown 

 teeth. Each fertile stem is terminated by a cone made up of 



