The Hydra logo that was the branding for the Hydra Project throughout most of its existence under that name. It was dropped when the Community changed name to Samvera in order to avoid a trademark dispute.
Two or so years into the Hydra project, around 2010, an on-line demonstrator was produced for the emerging software. The product was called Hydrangea. It proved difficult to keep up to date at a time of rapid development and was soon dropped - but it was in use long enough to get its own logo.