. Practical physiology of plants. Plant physiology; 1894. 214 DESMODIUM. [CH. VIII horizon instead of 30° as at first. These changes are graphically represented in the Power of Movement in Plants, p. 334, fig. 135. The ordinates represent the angle made with the vertical by the leaflet under obser- vation ; a fall in the curve thus represents a drop of the leaflet, 0° representing a vertically dependent position. The dotted line represents temperature, and is to be read in connection with the numbers 76° °F. on the right hand of the diagram. (262) Autonomous movements: Desmodium gyrans.
. Practical physiology of plants. Plant physiology; 1894. 214 DESMODIUM. [CH. VIII horizon instead of 30° as at first. These changes are graphically represented in the Power of Movement in Plants, p. 334, fig. 135. The ordinates represent the angle made with the vertical by the leaflet under obser- vation ; a fall in the curve thus represents a drop of the leaflet, 0° representing a vertically dependent position. The dotted line represents temperature, and is to be read in connection with the numbers 76° °F. on the right hand of the diagram. (262) Autonomous movements: Desmodium gyrans. The leaf of Desmodium gyrans represented in consists of one large and a pair of very minute leaflets. It is these which execute the movements for which the plant is celebrated. The point of each leaflet de- scribes a rough sort of circle or ellipse, but the movement being exceedingly jerky and irregular the circular course is not obvious. The movement does not occur at all unless the temperature' is about 22° C, and may be remarkably stimulated by a higher temperature, thus at 40° C. the circles are made at the rate of about two in three minutes. The experiment may be performed by immersing a leaf in cool water which is gradually heated. fig. 43. 1 This is only true of full-grown plants. Seedlings move at lower temperature: see Power of Movement in Plants, p. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Darwin, Francis, Sir, 1848-1925; Acton, Edward Hamilton, d. 1895; Lindley, Nathaniel Lindley, Baron, 1828-1921. sgn. Cambridge, University Press
Size: 884px × 2825px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectplantph, bookyear1894
