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tuberosus) grown under these two sets of conditions was very striking (Fig. 163). 

 In this case the lowland form was tall, with spirally arranged leaves, and the 



P M ^ 



Fig. 163. — Two plants of Helianthus tuberosus (Jerusalem artichoke), one grown in the 

 lowland (P), the other in the mountains (M); at the right the latter is enlarged (M'). 

 (After Bonnier.) 



Fig. 164. — Picea (spruce) seedlings', three years old, grown under like conditions but from 

 different stocks, i. seed from the Achental (in the Austrian Tyrol) at an altitude of 1600 

 m.; 2, seed from the same region, but at an altitude of 800 m.; 3, seed from Finland. 



whole plant was very similar to the common sunflower {Helianthus annuus), but 

 the alpine plant, grown at an altitude of 2300 m., was quite different in appear- 

 ance, being very much smaller, with almost no stem and with the leaves in a 



