The herbaceous stem of a Verbena melindres (?) laid horizontally, rose in 7 h. so much that it could no longer be observed on the vertical glass which stood in front of the plant.  The long line which was traced was almost absolutely straight.  After the 7 h. it still continued to rise, but now circumnutated slightly.  On the following day it stood upright, and circumnutated regularly, as shown in Fig. 82, given in the fourth chapter.  The stems of several other plants which were highly sensitive to apogeotropism rose up in almost straight lines, and [page 496] then suddenly began to circumnutate.  A partially etiolated and somewhat old hypocotyl of a seedling cabbage (2 3/4 inches in height) was so sensitive that when placed at an angle of only 23o from the perpendicular, it became vertical in 33 minutes.  As it could not have been strongly acted upon by apogeotropism in the above slightly inclined position, we expected that it would have circumnutated, or at least have moved in a zigzag course.  Accordingly, dots were made every 3 minutes; but, when these were joined, the line was nearly straight.  After this hypocotyl had become upright it still moved onwards for half an hour in the same general direction, but in a zigzag manner.  During the succeeding 9 h. it circumnutated regularly, and described 3 large ellipses.  In this case apogeotropism, although acting at a very unfavourable angle, quite overcame the ordinary circumnutating movement.

Fig. 183.  Beta vulgaris:  apogeotropic movement of hypocotyl from 19o beneath horizon to a vertical position, with subsequent circumnutation, traced on a vertical and on a horizontal glass-plate, from 8.28 A.M.  Sept. 28th to 8.40 A.M. 29th.  Figure reduced to one-third of original scale.

The hypocotyls of Beta vulgaris are highly sensitive to apogeotropism.  One was placed so as to project 19o beneath the horizon; it fell at first a very little (see Fig. 183), no doubt owing to its weight; but as it was circumnutating the line was [page 497] oblique.  During the next 3 h. 8 m. it rose in a nearly straight line, passing through an angle of 109o, and then (at 12.3 P.M.) stood upright.  It continued for 55 m. to move in the same general direction beyond the perpendicular, but in a zigzag course.  It returned also in a zigzag line, and then circumnutated regularly, describing three large ellipses during the remainder of the day.  It should be observed that the ellipses in this figure are exaggerated in size, relatively to the length of the upward straight line, owing to the position of the vertical and horizontal glass-plates.  Another and somewhat old hypocotyl was placed so as to stand at only 31o from the perpendicular, in which position apogeotropism acted on it with little force, and its course accordingly was slightly zigzag.