From the nodes spring whorls of similar but more slender branches.
The line of nodes rotates in a period of 18.612 years and the line of apsides in a period of 8.84 years.
The plant is readily propagated by cuttings, a piece of the stem bearing buds at its nodes will root rapidly when placed in sufficiently moist ground.
This section includes a number of families characterized by the backward extension of the prothorax to the tegulae and distinguished from the ants by the absence of " nodes " at the base of the abdomen.
Now we may resolve these trains by Fourier's theorem into harmonics of wave-lengths X, 2X, 3A, &c., where X=2AB and the conditions as to the values of y can be shown to require that the harmonics shall all have nodes, coinciding with the nodes of the fundamental curve.