Coralline algae are present in almost all areas inhabited by seaweeds and often give a deep pink coloration to the habitat. Numerous observations of coralline algae have shown that on crowded shores they often form associations with other plants or animals. Numerous characteristics have been employed in the various strategies for classifying the Corallinaceae on the generic level. There are two main schemes for grouping the Corallinaceae: nonarticulated genera and the articulated genera. The rich fossil record reveals that the Solenoporaceae existed at least until the Paleocene, whereas the first undoubted Corallinaceae has been recorded from the Jurassic. Coralline algae grow slowly, but their large numbers make them important in the production of organic and inorganic material in the oceans. As in most red algae, the cells of coralline algae are joined in filaments which are aggregated into thalli. The basis unit of vegetative structure is the filament, many of which are united into thalli.