On the Distribution of Honey-Glands in Pitchered Insectivorous Plants

THE four genera of pitchered insectivorous plants at present in general cultivation are Nepenthes, Sarracenia, Darlingtonia, and Cephalotus. Attention was drawn to the minute structure and physiological action of the first three of these by Sir J. Hooker in his celebrated presidential address to the British Association in 1874, while the structure and morphology of the last was treated of by my master, Prof. Dickson (Journal of Botany, 1878, 1881). Both observers pointed out an attractive surface studded with honey-glands, which constituted the lid part, a conducting surface, either of an exceedingly smooth nature (Nepenthes), or beset with small downward-directed hairs (Sarracenia, Darlingtonia, Cephalotus), and in most cases a glandular surface (Nepenthes, S. purpurea and Cephalotus), the secretion from which directly or indirectly assisted in digestion of animal products. In Sarracenia and Darlingtonia there was found in addition a detentive surface, covered with long deflected hairs.