Introduction

Sargassum echinocarpum is an endemic Hawaiian species in the Sargassaceae. The distribution of this family is throughout tropical and sub-tropical Southern Hemisphere waters. It is considered to exhibit the most complex morphology among the Fucales. S. echinocarpum is common in rocky intertidal areas and on reef flats.

S. echinocarpum, called limu kala by Hawaiians, is considered to be an edible limu, though it was often used to flavor foods rather than being consumed directly, due to the toughness of older parts. Limu kala also has a highly significant ceremonial or symbolic value, and was used medicinally, as well.

Tissues in this brown alga are differentiated into three main types, epidermis, cortex, and medulla. Their presence and appearance is related to the function of the different organs.

S. echinocarpum is golden to golden-brown in its upper parts (leaves and floats), while the stem and holdfast may be a very dark brown in color. Dark spots appear on the surface of floats and leaves; these are nonreproductive conceptacles. Reproductive conceptacles appear on receptacles near the joint of the leaf and the stem. They were small and apparently non-fertile at the time of collection (late November). Part of the life history of this species includes a yearly winter “dieback” of the upper part of the plant after reproduction, while the holdfast remains perennially on the substrate and regenerates a few months later.

The purpose of this study was to examine the anatomy of S. echinocarpum, and compare its tissues to analogous structures in terrestrial plants.

Main Page	Abstract	Materials & Methods	Results: Float	Results: Leaf	Results: Stem
Results: Holdfast	Discussion	References