Other Phaeophyceae Sphacelaria Sphacelaria tribuloides Meneghini with a propagule. In Sphacelaria , the cells behind the apex divide longitudinally without getting any wider, so that the thallus looks filamentous but is actually parenchymatous.
Vegetative reproduction is very common, by the production of propagules.
Photo on the Ceramium page. The hollow, net-like thalli of Hydroclathrus clathratus very distinctive. The large plants produce plurilocs, and the spores from these can reform the large thallus or give rise to a microscopic prostrate thallus. This in turn forms both unilocs and plurilocs. Cells from the plurilocs regenerate the prostrate thallus, and cells from the unilocs form the large plant.