Distromium decumbens (Okamura) Levring, 1940

Belleza, Dominic Franco C., Tateishi, Hiroto, Tanimae, Shin-Ichiro, Kobayashi, Taishun, Aota, Tomoyuki, Urasawa, Toshiki & Nishihara, Gregory N., 2025, An annotated list of brown seaweeds (Phaeophyceae) from Nakadori Island (northern Goto Islands, Nagasaki, Japan), Phytotaxa 694 (1), pp. 1-24 : 9

Distromium decumbens (Okamura) Levring, 1940

Japanese name: フタエオƯギ (futaeougi)

Basionym: Chlanidote decumbens Okamura, 1899

Type locality: — Japan (Boshyu, Enoshima, Prov. Hiuga, Prov. Tosa)

Description and remarks: —The thalli is prostrate, about 9 cm in width. The blades are flabellate and margins are entire with some areas having deep incisions, possibly due to herbivory. This is commonly observed attached to rocky substrate in Aokata where they share the substrate with Dictyota spp. in late spring.

This species lacks the in-rolled margins ( Kitayama 2011) found in other similar species like Padina spp. The specimen exhibits fine filamentous outgrowths from a portion of its margins and is a means of vegetative reproduction for this species ( Kajimura 1986).

Materials examined: —18ECS1-158-1