| Hydra viridissima | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Class: | Hydrozoa |
| Order: | Anthomedusae |
| Family: | Hydridae |
| Genus: | Hydra |
| Species: | H. viridissima |
| Binomial name | |
| Hydra viridissima Pallas, 1766 |
|
Hydra viridissima also known as the green hydra, is a cosmopolitan species of hydra found in both temperate and tropical fresh waters. The characteristic green colour comes from cells of the unicellular alga Chlorella within the cells of the gastrodermis.
When disturbed, the hydra retracts to a small green blob which is easily overlooked. Gently sweeping through a clean weedy pond and allowing the collected water and plant matter to stand in a jar will often reveal a hydra re-emerging after only a few minutes.