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A TEXTBOOK OF THEORETICAL BOTANY 



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Fig. 916. — Rubia peregrina. Transverse section of 

 stem showing stem wings formed as extensions 

 of the stem cortex. 



formed above ground, which spread more rapidly than the rhizomes and 

 may be up to 10 metres long. 



One of the best-known cases is that of the Strawberry (Fragaria vesca), 

 which spreads by runners with extreme rapidity. The runners come from 





Fig. 917. — Ronunculus repens. Plant with a runner bearing 

 adventitious roots at two nodes. 



the axils of the leaves on the flowering plant. They bear only reduced leaves, 

 each consisting of a pair of stipules with a small bristle between them. The 

 runner ends at the second node, with a rosette of normal leaves. From the 

 axil of a reduced leaf at the base of this rosette a new runner emerges, and 

 so on. The whole runner is therefore sympodial. Each rosette eventually 



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