A morphometric comparison of <i>Ecklonia kurome</i> (Laminariales, Phaeophyta) from Japan*

Abstract

SUMMARY A morphological comparison was made of Ecklonia kurome Okamura collected from seven localities, including a lectotype locality (Shirahama), in Japan. Morphometric characters and their size ranges were recorded as follows: the central lamina width (5.1–67.8 cm), the median fascia thickness (0.9–3.3 mm), the primary pinna width (2.2–24.0 cm), the ratio of width to length of the primary pinna (0.07–0.56) and the primary pinna number index (PPNI; 0.24–2.21). The results suggested that the morphological variations observed within this species were related to their habitat. A thick and distinct median fascia and an undulate central lamina margin were found on plants from moderate wave‐exposed locations. Plants having narrow primary pinnae with indistinct ruga were observed on shores facing open sea. Wide and thin plants grew in wave‐sheltered habitats. Flat plants were found on a shore exposed to a continuous strong current throughout the year. There were noticeable differences in morphology among the Tateyama, Tsuno, Aburatsubo and Tonoshima populations. The yellow and crisp primary pinna edge was a major characteristic of the Tateyama population. Narrow plants in which the central lamina and primary pinnae were half as wide as those of the Shirahama population were found in Tsuno. Wide and thin plants were observed in Aburatsubo. In this locality, the central lamina and primary pinnae were nearly three times wider but half the thickness of those of the Shirahama population. Flat plants grew in Tonoshima. The Muroto and Oki populations exhibited morphologically similar characteristics to the Shirahama population. A hollow stipe and slightly high PPNI value were found in the Muroto population, and a slightly low PPNI value was found on the Oki population.