Moorhens or marsh hens are members of the rail family Ralidae and of the genus Gallinula. They are closely related to coots. The livng species within the genus Gallinula are listed below. The ones with photos are highlighted in red.

Gough Island Moorhen, Gallinula comeri
Common Moorhen, Gallinula chloropus
Dusky Moorhen, Gallinula tenebrosa
Lesser Moorhen, Gallinula angulata
Spot-flanked Gallinule, Gallinula melanops
Black-tailed Native-hen, Gallinula ventralis
Tasmanian Native-hen, Gallinula mortierii

A related genus,
Porphyrio include a group of smaller moorhens called purple gallinules. The species involved are:

Purple Swamphen (formerly Purple Gallinule), Porphyrio porphyrio
Takahē (South Island Takahē) Porphyrio hochstetteri
Allen's Gallinule (Lesser Gallinule) Porphyrio alleni
American Purple Gallinule, Porphyrio martinica
Azure Gallinule, Porphyrio flavirostris
African Purple Swamphen (African Purple Gallinule) Porphyrio madagascariensis (formerly Porphyrio porphyrio)