Hydranthea have small smooth
hydrophores placed irregularly along their hydrorhiza, of variable length - though they tend to be shorter. They have elongated polyps along their stems. Their bodies are pale gold in color, with a thin white band below the
hypostome, an appendage on their mouth. Their tentacles, of which they have 30 per
whorl, are long and colorless and connected to each other at their bases by an intertentacular web. They have around two to three
Nematocysts between each set of tentacles on this web. Hydranthea have oval
gonophores, a reproductive structure, on their hydrorhiza. They are
dieoecious, with usually only one sex, male or female, present within a single colony. == Behavior ==