Two new species of Martensia (Delesseriaceae, Rhodophyta) from Jeju Island, Korea

Two new species of Martensia (Delesseriaceae, Rhodophyta) are described from Jeju Island, Korea. Martensia jejuensis is characterized by the thallus of long linear axes and a proximal membranous part (initial blade), the linear axes that are derived from the longitudinal lamellae of the latticework, the flabellate bladelets arising from the linear axes terminally and laterally, the leading margins of the latticework giving rise to spine‐like or spatulate projections at intervals, and tetrasporangia borne on the whole thallus except for the spatulate projections. Martensia bibarii is characterized by the fimbriate aspect, the ribbon‐like blade with lobes, the flabellate bladelets derived from the lobes of the blade, the bladelets bearing the fringe or the latticework distally, the fringe consisting of many fine and strap‐shaped lamellae, and tetrasporangia borne only on the blade.