Cystosphaera jacquinotii, a fucoid alga native to the Antarctic peninsula. Â The spherical structures are pneumatocysts, or floats which keep the lamina elevated in the water column and exposed to light. Â The clustered fingerlike projections are receptacles, which contain reproductive structures (antheridia and oogonia). Â Not a kelp! Â Photo by Chuck Amsler.Â











