Page:Darwin - On the movements and habits of climbing plants.djvu/18

(Dicotyledons, continued.)

Hoya carnosa (Asclepiadaceæ) made several circles in from 16 h. to 22 h. or 24 h.

Convolvulus major (Convolvulaceæ) moves against the sun. Plant placed in room with lateral light.

1st circle … 2 h. 42 m.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Semicircle, from light in 1 h. 14 m., to light 1 h. 28 m.: difference 14 m.
2nd circle … 2 h. 47 m.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Semicircle, from light in 1 h. 17 m., to light 1 h. 30 m.: difference 13 m.

Convolvulus sepium (large-flowered cultivated var.) moves against the sun. Two circles, each in 1 h. 42 m.: difference in semicircle from and to light 14 m.

Iponuea jucunda (Convolvulaceæ) moves against the sun, placed in my study, with windows facing the north-east. Weather hot.

1st circle 5 h. 30 m.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Semicircle, from light in 4 h. 30 m., to light 1 h. 0 m.: difference 3 h. 30 m.
2nd circle 5 h. 20 m. (Late in afternoon: circle completed at 6 m. 40 h. p.m.	$\scriptstyle {\left.{\begin{matrix}\ \\\\\ \ \end{matrix}}\right\}\,}$	Semicircle, from light in 3 h. 50 m., to light 1 h. 30 m.: difference 2 h. 20 m.

We have here a remarkable instance of the power of light in retarding and hastening the revolving movement.

Rivea tiliæfolia (Convolvulaceæ) moves against the sun, and made four revolutions in 9 h.; so that each, on average, was performed in 2 h. 15 m.

Plumbago rosea (Plumbaginaecæ) follows the sun. The shoot did not begin to revolve until nearly a yard in height; it then made a fine circle in 10 h. 45 m. During the next few days it continued to move, but irregularly. On August 15th the shoot followed, during a period of 10 h. 40 m., a long and deeply zigzag course and then made a broad ellipse. The figure thus traced altogether apparently represented three ellipses, each of which averaged 3 h. 33 m. for its completion.

Jasminum pauciflorum, Bentham (Jasminaceæ), moves against the sun. First circle in 7 h. 15 m., second circle rather more quickly.

Clerodendrum Thomsonii (Verbenaceæ) follows the sun.

		h.	m.
April 12,	1st circle . . . . . .	5	45	(shot very young).
April„ 14,	2nd circle„ . . . . . .	3	30
April„ 18,	semicircle . . . . . .	5	0	(directly after the plant was shaken in
April„ 19,	3rd circle„ . . . . . .	3	0	[being moved).
April„ 20,	4th circle„ . . . . . .	4	20

Tecoma jasminoides (Bignoniaceæ) moves against sun.

		h.	m.				h.	m.
March 17,	1st circle	6	30		March 28,	3rd circle	8	30	(very cold day).
March„ 19,	2nd circle„	7	0		March„ 24,	4th circle„	6	45

Thunbergia alata (Acanthaceæ) moves against sun.

		h.	m.				h.	m.
April 14,	1st circle	3	20		April 18,	3rd circle	2	55
April„ 18,	2nd circle„	2	50		April„ 18,	4th circle„	3	55	(late in afternoon).

Adhadota cydoaæfolia (Acanthaceæ) follows the sun. A young shoot made