Corals can reproduce both asexually or sexually. The term asexually can be referred to as vegetative and the term sexually as generative. Through asexual reproduction, a coral can make a clone of itself. The two methods of asexual reproduction are able to eventually give rise to an entire colony, these are budding and longitudinal division. Individual corals can reproduce through by transversal division. Coral colonies are able to live for a few hundred years.

Coral colonies grow in a similar manner to those of plants.
Colonies can grow in the following manner:

1)    by producing stolons
Stolons horizontally grow cell layers. They look like a system of roots that fix the whole colony to substrate. New polyps grow on stolons.
2)    by monopodial growth
This term means that the trunk of the colony is made by the oldest polyp. The trunk grows during growth of new polyps. The oldest polyp is always on top of the colony.
3)    by sympodial growth
This colony does not produce a trunk. New polyps offshoot along the edges of adult polyps. The youngest polyps are always on top of colony.
4)    by dychotomic growth
Dychotomic growth means that the corals divide symmetrically. Since all polyps grow simultaneously, neighbor polyps are the same age.

Budding

In the process of budding, a young coral individual grows out from the adult (parent) polyp. This is the way a colony grows. Within the reach of the oral disc or beyond the wreath of tentacles on an adult polyp, a daughter polyp forms. The daughter polyp has two cell layers: ectodermis and gastrodermis. As the daughter polyp grows, it produces a coelenteron, tentacles and a mouth. Sometimes, the young polyp can originate beyond the wreath of tentacles. When this happens, the distance between the polyps increases which causes development of coenosarc. The cenosark is the common body of the colony. New polyps grow on the coenosarc. Coenosarcs produce the coenosteum. The coenosteum is the colony’s exoskeleton.

This drawings show how a new polyp originate in process of budding.

Longitudinal Division

Longitudinal division is a common reproduction method. In longitudinal division, the coral polyp begins to broaden. It then divides into a coelenteron and mesenteries. Next, the mouth divides and tentacles encircle the new mouth. The difference between budding and longitudinal division is that during budding, the parent polyp produces a smaller polyp, whereas after division, the two polyps are identical. There is no distinction of parent and daughter polyps in a division. Individual polyps divide according to the radial arrangement of septa. Every new part has to complete its missing parts of the body and exoskeleton.

Transversal Division

Individual corals are able to reproduce by transversal division. Polyps and the exoskeleton divides transversally into two parts. One of them has the basal disc. The second has the oral disc. The two new polyps must complete missing parts of the body and exoskeleton in order to function.

Fragmentation

Last method for coral colonies to propagate is through a process of fragmentation. A piece of colony can actually be broken off to grow a clone.

Coral Reefs