NMH
Banned
Can they.
Hydras certainly can;
"When conditions are harsh, often before a cold winter, sexual reproduction occurs in some hydras, producing unfertilized eggs. These eggs are then fertilized by sperm from testes which form on the external surface of the stalk. The fertilized eggs secrete a tough outer coating and, as the adult dies, these resting eggs fall to the bottom of the lake or pond to await better conditions, whereupon they hatch into miniature adults. Hydras are considered to be hermaphrodites."