or Chickweed. See Botany Index.

The common chickweed affords a remarkable instance of what is called the sleep of plants; for, every night, the leaves approach in pairs, so as to include within their upper surfaces the tender rudiments of the new shoots; and the uppermost pair but one at the end of the stalk are furnished with longer leaf-blades than the others; so that they can close upon the terminating pair, and protect the end of the branch.