Cyathea inquinans is a species of tree fern native to southwestern Sulawesi and possibly the Maluku Islands, where it grows in montane forest at an altitude of 2000-2800 m. This plant has an erect trunk that is usually 2-4 m tall. Fronds may be bi- or tripinnate and 1 m or more in length. The stipe is covered in scales. These scales are either large, red-brown, thin, with narrow fragile edges, or small, with a red apical seta. Sori are borne near the fertile pinnule midvein. They are protected by thin, brown indusia.