Fig. 135. Equisetu7n arvense, a common horsetail: 1, three fertile shoots rising from 

 the dorsivertral stem, showing the cycles of coalesced scale-leaves at the joints 

 and the terminal strobili with numerous sporophylls, that at a being mature; 2, 

 a sterile shoot from the same stem, showing branching; S, a single peltate sporo- 

 phyll bearing sporangia; A, view of spnrophyll from beneath, sho\\ ing dehiscence 

 of sporangia; 5, 6, 7, spores, showing the unwinding of the outer coat, which aids 

 in dispersal. — After Wossidlo. 



