They are propagated by cuttings, or from the leaves, which are cut off and pricked in welldrained pots of sandy soil, or by the scales from the underground tubes, which are rubbed off and sown like seeds, or by the seeds, which are very small.
It is from the actively growing callus developed at the surface of the wounded tissues of cuttings, buddings, prunings, &c., that the healing and .renewal of tissues occur of which advantage is taken in the practice of what might well be termed plant surgery.
Every time a carpenter saws fresh timber with a saw recently put through wood attacked with dry-rot, he risks infecting it with the Fungus; and similarly in pruning, in propagating by cuttings, &c.
Slips in cuttings or embankments18 23.
On the one hand he may make the line follow the natural inequalities of the ground as nearly as may be, avoiding the elevations and depressions by curves; or on the other he may aim at making it as nearly straight and level as possible by taking it through the elevations in cuttings or tunnels and across the depressions on embankments or bridges.