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Arbeiten. Bot. I. Wurzburg Heft. III 1872.

De Vries. Ursachen der Richtung bilat. sym. Pflanzentheile

p 228 cutting off leading shoot making horizontal upright shows me much not understood

228— only tensionless organs are positively geotropic

229 Nodding flowers all due to weight

(In chapter on Epinasty, I ought to quote Sa)

230 Sachs attributed changes of position to leaves from bud to maturity to growth along upper side.— as first explained by Sachs, (Lehrbuch) 2d Edit.

234 Strawberry Runners apheliotropic with sun-light (quote) & apogeotropic when weight of terminal bud removed. p. 274 do p. 271— De V.

236 Frank showed that leaves become vertical in darkness, attributes this to apogeotropism, & defective nutation stopping epinasty.

237, 8 Weight of part is cause of much bending very important

239 Here speaks of leaves of plants turned upside down all bending to Light

244. mid-rib when freed from blade always curve downwards.

251. General rule — petiole & midrib apogeotropic — & epinastic.— X— Important

252 257 accounts for "nutation" of leaves & quotes Sachs. by Epinasty & usually subsequently by hyponasty—

254. The 2 rules apply to the inclined, vertical & horizontal leaves.

255 experiments all tried on leaves in last stage of growth.

258 gradation from leaves in which petiole passes invisibly into lamina — into 2 stems stems angularly bent which bends more than in other parts,— to true pulvinus

On origin of Pulvinus

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258. nothing to make doubt same action when there is a pulvinus or "polster" or when not — but he then speaks of upper surface of "polster" growing ⸮ quickest, which no doubt Pfeffer wd say was due to greater expansion cells.

257 Heliotropic experiment — 3 metres from N. window

261. Out of those experiments it follows " in vielen fallen Kein Einfluss des Heliotropismus.—" always positive & never overcome epinasty — Even sun-light did not conquer epinasty.—

271 repeated with respect to branches.

262— Weight affect curvature.— 276.—

263 removal of lamina affects growth

271. Stolon of Strawberry with sun-light apheliotropic

276. a sentence which makes me think his negative heliotropic observation refer only to petioles & midrib

[Movement in plants, p. 440: "De Vries has shown* that the more or less horizontal position of leaves is in most cases influenced by epinasty, by their own weight, and by apogeotropism. A young cotyledon or leaf after bursting free is brought down into its proper position, as already remarked, by epinasty, which, according to De Vries, long continues to act on the midribs and petioles. Weight can hardly be influential in the case of cotyledons, except in a few cases presently to be mentioned, but must be so with large and thick leaves. With respect to apogeotropism, De Vries maintains that it generally comes into play, and of this fact we shall presently advance some indirect evidence. But over these and other constant forces we believe that there is in many cases, but we do not say in all, a preponderant tendency in leaves and cotyledons to place themselves more or less transversely with respect to the light.
* 'Arbeiten des Bot. Instituts in Würzburg,' Heft. ii. 1872, pp. 223-277."]