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Heliotropism - Books & Papers.

Pfeffer p. 7 first a decrease of expansion in joints & vice versa with darkness

p. 9 Heliotropism with & without growth - confined to pulvinus.

p. 121 loss of sensibility, before loss of periodicity from Darkness.

[Pfeffer, Die Period. Bewegungen, 1875.]

Wiesner - Die Undulirende Nutation

p. 6 on Heliotrop of stem placing leaves in right position - while that of leaves places themselves in right position

(must quote)

p. 7. H. Müller of Thurgau showed that heliotropically bent stem is curved back through apogeotrop. must quote in length

[Movement in plants, p. 465, n: "It appears from a reference in Wiesner ('Die Undulirende Nutation der Internodien,' p. 7), that H. Müller of Thurgau found that a stem which is bending heliotropically is at the same time striving, through apogeotropism, to raise itself into a vertical position."]

Godlewski - Bot. Z. 1879. p 119. The retarding influence of light on growth well known to all Botanists - by Prantl Proved beyond doubt for stems by Sachs, & Leaves & Vines

p. 119 - attributes it to light lessening the extensibility of the stretched layer of the cells or cell.

[Movement in plants, p. 485, n: "Emil Godlewski has given ('Bot. Zeitung,' 1879, Nos. 6-9) an excellent account (p. 120) of the present state of the question. See also Vines in 'Arbeiten des Bot. Inst. in Würzburg,' 1878, B. ii. pp. 114-147."]

[111v]

Sachs Physiologie Heft II. B. 2.

Prantl. - Heft III. - growth of leaves Vines