''Eudendrium racemosum'' is a marine

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

cnidaria Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, ...

, a hydroid (

Hydrozoa Hydrozoa (hydrozoans; from Ancient Greek ('; "water") and ('; "animals")) is a taxonomy (biology), taxonomic class (biology), class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline wat ...

) in the family

Eudendriidae Eudendriidae is a taxonomic family of hydroids (Hydrozoa). The family contains around 85 species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can pro ...

. It was described by Cavolini in 1785.World Register of Marine Species
Retrieved November 9, 2012 Hydroids are one of the most abundant organisms in hard-substratum benthic communities, more specifically in temperate seas, such as the Mediterranean. Similar to most modular organisms, they have high growth rates. In fact, ''E racemosum'' has been frequently found in northeastern Spain, specifically in Medes Islands, showing a maximum population density in summer with a minimal density during the winter (this is when it typically exists as dormant stolon). Their rapid growth coupled with their ability to store the necessary material to survive the winter is due to their efficient feeding and digestive methods.

References

racemosum Animals described in 1785 {{Eudendrium-stub