Image of Cystoseira osmundacea

Description:

The thallus of this perennial brown alga is being swept horizontally by the ocean's surge. The holdfast anchors the kelp at a depth of 15 m. A short, tough stipe bears flattened blades. From the tips of the blades each year the alga will send slender reproductive fronds to the sea surface where eggs or sperm will be released. Fertilization will lead directly to another thallus.