Atheris nitschei is a species of highly venomous snake, a viper in the subfamily Viperinae of the family Viperidae. The species is native to Africa. There are no subspecies that are recognized as being valid.
The specific name, nitschei, is in honor of German zoologist Hinrich Nitsche (1845–1902).
The 1906 junior synonym, A. woosnami, was in honor of Kenyan game ranger Richard Bowen Woosnam (1880–1915), who later fought in World War I and was killed in action at Gallipoli.
Common names for A. nitschei include Great Lakes bush viper, Nitsche's bush viper, black and green bush viper, Nitsche's tree viper. sedge viper, green viper, bush viper.
Atheris nitschei is a relatively large and stout bush viper, growing to an average total length (including tail) of 60 cm (24 in) and a maximum total length of at least 80 cm (31 in). The males are smaller than the females.
Atheris nitschel is found in forests of the Central African Albertine Rift, in southern and eastern DR Congo, Uganda, western Tanzania, Rwanda, Burundi, and Zambia.
The type locality is listed as "Mpororosumpf, Deutsch-Ost-Afrika".
Preferred habitats of A. nitschei are wetland and meadow areas, and elephant grass marshes, along small streams, sometimes in scrub and bush in valleys at higher elevations, and in mountain forests up to the bamboo zone at 1,600–2,800 m (5,200–9,200 ft) altitude. It is common in papyrus reed around small lakes.
Atheris nitschi has highly toxic venom like others in the Atheris genus. Not much is known about their venom but envenomation has caused severe bleeding and hemorrhaging.
A. nitschei is viviparous.
