Cyathea decrescens is a species of tree fern endemic to Madagascar. The trunk is erect, 2–3 m tall and 10–12 cm in diameter. It usually has characteristic elliptical scars caused by fallen stipe bases. Fronds are bipinnate and 1-1.5 m long. The fronds may be densely pubescent and the lower pinnules are sometimes separated from the others as well as being reduced. The rachis and stipe are brown in colouration and bear narrow, dark brown scales. Sori are large, round and covered by fragile, brown indusia.