Drosera erythrogyne is the longest species of sundew, with stems that are known to grow three meters long! It is bright green and glabrous except for the sepals, which have a dense covering of glands. The bright green stem is fleshy and wavy, which along with the arched petioles, gives the plants a messy profile. The stems are glabrous. It is named after its deep red ovaries which are visible in open blooms. The leaves are mostly slightly notched at the top, although some may appear round.

Drosera erythrogyne is found near swamps and next to granite outcrops along the south coast of Western Australia. It is a strong climber, using its leaves to latch onto surrounding vegetation. The species gets particularly large in the regrowth after a bushfire.

The species is contrasted with the similar Drosera pallida by its slightly reniform leaves, which remain bright green (D. pallida has orbicular lamina, which are often red).