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Rauwenhoff.— Archives Néerlandaises t XII — sur les "Formes Anormales des Plantes qui croissent dans l' Obscureite" (separate copy)

I must not say that leaves not growing in darkness, which stems do is cause of form not circumnutating — for some leaves do grow greatly— Darkness disturbs all functions & affects (p. 25) tissue of stamen all parts

p.7. Batalin shows that with little light Cots will grow & yet remain yellow (p. 8 Gramineæ & other monocotyledons p. 37 leaves of grow in darkness, probably some connection with the fact of them circumnutating in darkness.)

[in margin:] Keep — Put in Chapter wh I speak of Darkness Light deciding curvature

p. 30 & 31. germination of seeds in dark— radicles short.

p. 32 shoots in darkness grow vertically & this looks as if epinasty failed, for de Vries wd have discovered apheliotropism.—

[Movement in plants, p. 443: "It must be the result of some periodical change in the conditions to which they are subjected, and there can hardly be a doubt that this is the daily alternations of light and darkness. De Vries states in the paper before referred to, that most petioles and midribs are apogeotropic;* and apogeotropism would account for the above rising movement, which is common to so many widely distinct species, if we suppose it to be conquered by diaheliotropism during the middle of the day, as long as it is of importance to the plant that its cotyledons and leaves should be fully exposed to the light.
* According to Frank ('Die nat. Wagerechte Richtung von Pflanzentheilen,' 1870, p. 46) the root-leaves of many plants, kept in darkness, rise up and even become vertical; and so it is in some cases with shoots. (See Rauwenhoff, 'Archives Néerlandaises,' tom. xii. p. 32.) These movements indicate apogeotropism; but when organs have been long kept in the dark, the amount of water and of mineral matter which they contain is so much altered, and their regular growth is so much disturbed, that it is perhaps rash to infer from their movements what would occur under normal conditions. (See Godlewski, 'Bot. Zeitung,' Feb. 14th, 1879.)"]

p 38 Petioles grow to great length in darkness — so supposed law does not even hold good with whole leaf & chief seat of movement.

I must say no explanation why ci circumnutation of leaves including petioles fail in darkness more than stems,— for some petioles increase more in length.