Hormogonia

This gives the hormogonia filaments time to move into a more accomodatable environment or to create symbioses with other organisms (Such as Gunnera (see heterocyst page)).
The formation of hormogonia is essential for the formaiton of the Gunnera-Nostoc Symbiosis (cyanobacteria without the ability to differentiate into hormogonia were found to not be able to infect Gunnera at all)
The acidic mucilage secretion of the Gunera species contacined protein signalling molecules (Hormogonia Inducing Factor (HIF)) which induced the differentiation of cyanobacteria into hormogonia.
Cyanobacteria prefer conditions of pH neutrality or higher so the hormogonia will move away from this acidic mucilage into the Gunnera glands.

Hormogonia are small filaments of cyanobacteria lacking heterocysts, akinetes or vegetative cells.
They are capable of motility (unlike normal cyanobacteria) through gliding motility. This does not require flagella, but instead utilises ejection of polysaccharide slime from from jets at the end of the cells.

Due to the lack of heterocysts and vegetative cells, hormogonia do not have the function of either photosynthesis or nitrogen fixation.
They do however, dedifferentiate back into normal filaments after around 72-96 hours.