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Jan 4th 77/ The German in Jahr Buch (Frank) says leaves of monocots grow only at base without sheaths, & this probably accounts for non-heliotropism of young Canary-grass leaves — Full grown seedlings of Celery not being heliotropic probably depends on growth completed. All this shows (together with bending being less or none at bases of stems of seedlings) that growth & Heliotropism intimately connected.— We might think that lower part did not grow on one side & bend unless growth was first started in the sensitive zone.— But The effects of painting 1/2 vertical face, shows that some change is transmitted with

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great accuracy. This change is probably altered altered tension & I presume is instantly followed by growth— or perhaps a change of tension cannot be effected except in parts still capable of growth.