Darwin-Hooker Letters : Letter from C. R. Darwin to J. D. Hooker [8 February 1864]
Darwin, Charles Robert
Darwin-Hooker Letters
<p style='text-align: justify;'>Compares <i>Clematis</i> and <i>Tropaeolum</i> with respect to touch response. <i>Tropaeolum</i> shows a momentary response and quick recovery. <i>Clematis</i> takes hours to respond, and shows no recovery.</p><p style='text-align: justify;'>CD can show the gradations between leaves and tendrils, but how a branch passes into a tendril utterly puzzles him.</p>