FIG. 4. "EQUISETUM ARVENSE." (AFTER WOSSIDLO, FROM 

 STRASBURGER.) 



From " An Introduction to Structural Botany" by D. H. Scott. 



and 2, General view of plant, showing underground rhizome, bearing roots, 

 with fertile and barren upright stems, i, Fertile stems ; a, ripe cone. 

 2, Much-branched barren stem ; a (on rhizome), tubers. 3, Single 

 stalked scale from cone, showing spore capsules. 4, Similar scale from 

 below ; sporangia splitting. 5, Young spore, with elaters not yet ex- 

 panded. 6, Mature spore in damp condition ; elaters curled up. 7, The 

 same in dry condition ; elaters expanded. Figs, i and 2 reduced ; Figs. 3 

 and 4 magnified slightly ; Figs. 5, 6, and 7 very highly magnified. 



