Fungi, liverworts, horsetails, and ferns, can be found on the island, along with flowering plants, such as the narcissus anemone, lupines, and orchids.

Segula hosts vegetation typical to the Aleutian Islands, largely moss, lichens, and heath, in addition to sedges, grass, fungi, various herbs, fern, and flowering plants such as Narcissus anemone, lupines, and orchids.

Anemone narcissiflora (Narcissus-flowered anemone) is a herbaceous perennial in the genus Anemone and the buttercup family.

The name of the species has been in dispute and some have listed it as Anemone narcissifolia but Anemone narcissiflora was proposed for conservation.