This section is from the book "The Gardener's Monthly And Horticulturist V20", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
Miss M. M. writes: I have just finished Darwin's Insectivorous Plants" and see in Field and Forest for November, that C. de Candolle has been investigating the structures and movements of the leaves of' Dionoea muscipul'a with the following results: The absorption of animal matters is no direct advantage to the leaves, and not necessary for the development of the plant..
2. The marginal appendages and edge of the leaf are distinct from the remainder of the leaf and their motion is not simultaneous with that of the"clappers".
3. The stellatea hairs and glands are developed from the epidermis, but the sensitive hairs from the sub-epidermal tissues.
4. Stomata exist on both sides of the leaf, but only on the under sides of the"clappers".
5. The structures and developments of the leaves suggest the hypothesis that the movements of the"clappers"' are due to variable turgescense (absorptions of sap) on upper parenchymal surface alone.
6. Sensitive hairs are the active organs that convey the impulse of irritation direct to the sub-epidermal tissues. - Bot. Zeitung, Oct. 1877.