The cause of plagiotropy in maritime shore plants 15 

 Table HI. 1, 2 and 3 Ä. prostratum; 4 A. pat. prostratum, 5 and 6 Leont. autumnalis. 









July 5 



July 11 



Deviation 



1 



upper pair 



upper angle 



19, 28 



78, 88 



+ 59, +60 



lower angle 



82, 68 



52, 42 



+ 30, +26 



lower pair 



upper angle 



26, 35 



80, 90 



+ 54, +55 



lower angle 



94, 72 



86, 66 



+ 8, + 6 



2 



upper pair 



upper angle 



33, 31 



84, 83 



+ 51, +52 



lower angle 



64, 60 



60, 33 



+ 4, + 27 



lower pair 



upper angle 



30, 28 



60, 78 



+ 30, +50 



lower angle 



75, 82 



70, 61 



+ 5, + 22 



à 



upper pair 



upper angle 



24, 29 



71, 86 



+ 47, + 57 



lower angle 



76, 67 



57, 44 



+ 19, + 23 





upper angle 



20, 25 



54, 86 



+ 34, + 61 



lower angle 



106, + 88 



100, 88 



+ 6, + 0 



4 



upper pair 



upper angle 









lower angle 



15, 35 



14, 26 



+ 1, + 9 



« 



lower pair 



upper angle 



32, 29 



77, 67 



+ 45, +38 



luwer angle 



65, 74 



57, 60 



+ 8, + 14 



5 







108 



70 



+ 38 



6 







104 



80 



+ 34 



It is obvious, as a result of these experiments, that these plants are negatively 

 geotropic in darkness, since the tips of the branches (upper angles) now stand more 

 or less vertically. Similar experiments with rosette plants (Taraxacum, Leontodon, 

 Planiago coronopus) show that the leaves of these plants — in the open horizontally 

 expanded — take up a vertical position in darkness and in weak light (see plate). 

 Table IV shows the result of an experiment with plants kept for only 4 hours in 

 the dark room. Only the angles formed by the tips of the branches with the horizon 

 have been measured. In Glyceria maritima the angles formed by the uppermost 

 internodes of the stems with the perpendicular have been measured. The strongly 

 sub-horizontal position of these stems should be noted (see plate; also Leontodon 

 autumnalis fig. 4 and Table III). 



