(After Allman.) logy as the monopodial or racemose, and the sympodial or cymose types respectively; each is characteristic of one of the two sub-orders of the Hydroidea, the Gymnoblastea and Calyptoblastea.
In the sympodial method of budding, on the other hand, the founder-polyp is of limited growth, and forms a bud from its side, which is also of limited growth, and forms a bud in its turn, and so on (figs.
In a colony formed by sympodial budding, a polyp always produces first a bud, which contributes to the system to which it belongs, i.e.
- Diagram of sympodial 18) there is formed a main stem budding, uniserial type, shown on tithe i ma in t emeafh r m s polyp in four stages (1-4).
- Diagram of sympodial budding, system, from which simple unbranched Plumularia-type.
- Diagram of sympodial budding, biserial type, shown in five stages (1-5).
Solitary polyps are unknown in this sub-order; the colony may be creeping or arborescent in form; if the latter, the budding of the polyps, as already stated, is of the sympodial type, and either biserial, forming stems capable of further branching, or uniserial, forming pinnules not capable of further branching.
The most generally accepted explanation is the "sympodial" one.
Where the plant persists by means of a sympodial rhizome, or in Cyclamen by means of a tuber formed from the swollen hypocotyl.