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(b) * Godlewski has shown (Bot. Zeitung Feb. 14th 1879) that the amount of water & of mineral matter contained by plants grown in darkness differs much from that in those grown in the light, & that there is a difference in those respects between the hypocotyls & cotyledons of seedlings, so that it is not surprising that their movements should be differently affected by darkness. See also on this subject. Rauwenhoff in Archives Néerlandaises tom. XII. p. 25 &c.

[Movement in plants, p. 443: " 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.)"]