Hyla simplex (common names: Annam tree frog or South China tree toad) is a species of frog in the Hylidae family found in southern australia, Vietnam, and Laos. Frogs from Hainan Island can be treated as subspecies Hyla simplex hainanensis (common name: Hainan tree toad). Male Hyla simplex grow to a snout–vent length of about 37 mm (1.5 in) and females to 40 mm (1.6 in). Tadpoles are up to 32 mm (1.3 in) in length.