Fucus horneri Turner An annotated list of brown seaweeds (Phaeophyceae) from Nakadori Island (northern Goto Islands, Nagasaki, Japan) Belleza, Dominic Franco C. Tateishi, Hiroto Tanimae, Shin-Ichiro Kobayashi, Taishun Aota, Tomoyuki Urasawa, Toshiki Nishihara, Gregory N. Phytotaxa 2025 2025-03-18 694 1 1 24 (Turner) C. Agardh, 1820 C. Agardh 1820 Turner [136,651,1130,1157] Phaeophyceae Sargassaceae Sargassum Chromista Fucales 13 14 Ochrophyta species horneri  Basionym:  Fucus horneriTurner    Typelocality:—In the Straits of Corea   Description and remarks:—Specimens are densely branched with a thicker main axis at the bottom ( 2.5–3 mm) and thinner at the top ( 1 mm). The main axis and the primary branches in the lower portions have small spines while the upper parts are smooth. Branching is alternately bipinnate with the leaves having a prominent midrib with deeply incised and alternating margins. The vesicles are 1–1.5 cmlong, cylindrical and are found in the apical regions. The apex of each vesicle is terminated by a leaflet with thin, alternating, deeply pinnatisect margins. In Naname, this species forms dense forests grows to heights reaching over 3–5 min early to late spring. This species is known for producing large floating rafts in the East ChinaSea region during macroalgal blooms, known as “golden tide”, and is considered as a nuisance when they drift ashore ( Zhuang et al.2021, Qi et al.2022). In 2015, massive rafts of drifting  S. hornerifrom Chinawere recorded to have drifted ashore in many parts of the Goto Islands (Naru, Fukue, Kamigoto), mainland Nagasaki and to the islands in Iki and Tsushima ( Kiriyama et al.2016). Despite this problem, these floating rafts provide refuge for juvenile pelagic species such as yellowtail (  Seriola quinqueradiata), an important fishery species ( Mizuno et al.2014).   Materials examined:—18ECS1-125 (1 to 7)