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PRINCIPLES OF PLANT-TERATOLOGY. 



3, DIRECTION OF GROWTH. 



The Various Directions. 



1. Horizontal Shoots. — The change of direction which 

 the stem or branches, or both, may assume in their 

 growth is instanced by various phenomena. 



The main shoot or its branches may become hori- 

 zontal in their growth as in a variety of the spruce 

 which is completely prostrate. Gloebel describes and 



Fig. 33. — Ranunculus Lingua. Erect shoot developing into a runner (r) 

 at apex. (After Klebs.) 



figures the tip of a stolon of enchanter's nightshade 

 (Givcsea intermedia) which had already turned upwards 

 above-ground and was growing in a vertical direction 

 and about to produce foliage-leaves, but was induced 

 to grow downwards again beneath the soil. Klebs 

 grew a plant of the greater spearwort (Ranunculus 

 Lingua) in a warm manure-bed, when the apex of the 

 shoot developed a stolon in place of a continuation of 

 the erect leafy stem (fig. 33). 



He made a cutting of the inflorescence of the great 



