The Sad Asexual Life of Cyanidium

Cyanidium caldarium is a completely asexual organism. Unlike many rhodophyta, which reproduce by cell division, Cyanidium produces four endospores, which grow inside of the cell until they break out of the mother cell and float off to develop into adult cyanidium.

Endospores forming in lower left and upper right corner.  Image from

In the above picture, endospores can be seen developing in the lower left and upper right.

These endospores can grow on many different types of strata including rocks, soil, debris, and fallen logs. Congregations of this alga often form thick mats over the surface of the water.

Cyanium algal mat.  Image courtesy of Dr. D. Ward from