LAYERING

Some plants, such as the Echinidorus species or the marine algae from the Caulerpa genus, produce a horizontal aerial stem, known as a runner (or stolon). A young plant then grows out of this, producing roots that enable it to establish itself in the bed, either spontaneously, or with added help from the aquarist, who may have to encourage it to take root. After about a week, the roots will have grown sufficiently to allow the runner to be cut off. In the case of the Congo fern, this produces a rhizome that grows slowly, with new leaves appearing on it. If you cut off this rhizome between two leaves, you are left with two independent plants.

Marine algae of the Caulerpa genus multiply by extending a runner, which sprouts new leaves