114 D. P. Penhallow — Tendril Movements. 



With reference to conditions of humidity, it is found that 

 tendrils 6ab and 1 gave their minima of movement during pleas- 

 ant weather, while the plant was apparently in an active con- 

 dition. The rates per minute were, O047, and - 21 cm respect- 

 ively. Tendril 76, 9, 5bc, and 3 gave 0-08, 0*02, 0043, and 

 O013 cm respectively during a time of great moisture, and even 

 rain. 8c gave 0'025 cm during the time of a heavy fog and cold, 

 east wind. The remainder, 4, 7a, 2, Sb, 86, and 5a gave, re- 

 spectively, 0-031, 0-053, 0-18, 0-10, 0-166, and 0-13 cm , at times 

 when transpiration was excessive, as shown by the drooping 

 leaves and terminals, and always during a very bright sun. 



Dextrorse and Sinistrorse movements.— -The circum nutation of 

 the tendril tip may commence in a direction with the sun or the 

 reverse. Movement in either direction is by no means con- 

 tinued during the entire period of activity. Motion in one 

 direction may soon be succeeded by movement in the opposite 

 direction, one alternating with the other constantly. The 

 dextrorse motion for all the observations taken aggregated 

 1622-10 cm . The sinistrorse amounted to 1400-95 cm ; and the 

 ratio of one to the other was, therefore, as 1 : 0*86. We see in 

 this a very striking approach to equality in the two move- 

 ments. 



Terminal Bud. 



In the terminal bud we have to deal with a movement en- 

 tirely independent of the irritation of contact, but accompany- 

 ing a rapidly elongating axis which develops leaves and flow- 

 ers, as well as tendrils, first upon one side and then upon the 

 other at alternating nodes. 



The greatest movement occurred just before noon, but under 

 conditions of great humidity. The least movement took place 

 at night, also under conditions of great humidity, In either 

 case there was nothing to indicate other than a normal condi- 

 tion of the plant. As in the tendril, we here notice a move- 

 ment to the right and left, the latter being exceeded by the 

 former by 23*30 cm . There is in this a very evident tendency 

 to excess of dextrorse movement, but it is a fair question, to be 

 decided only by more extended observations, if there is not or 

 should not be as great equality here as in the movement of the 

 tendril. In the growth of the vine, as well as of the squash, 

 we have in the results obtained still further proof of the influ- 

 ence of meteorological conditions, as already shown. 



[To be continued.] 



