Family Description:
Members of this family are cushion-shaped or globular and rather spongy. They are composed of aggregated filaments that are differentiated into a medulla of large, colorless cells and a cortex of small-celled filaments.

Species description:
When mature, Sea Cauliflower forms yellowish-brown, hollow, globular to deeply convoluted thick-walled cushions about the size of grapefruit. If you press a piece of this species between your fingers it disintegrates easily into its constituent filaments (in contrast to the thin, smooth-walled sacs of Colpomenia). When very immature it is easily confused with young Studded Sea Balloons (Soranthera ulvoidea). The great Swedish botanist, Carolus Linnaeus, thought that Sea Cauliflower was a jelly fungus, hence the early name.

Sea Cauliflower is an annual that grows either on rocks, or, more frequently, as an epiphyte on several other species of algae in or out of tidepools. It is often abundant, forming a peculiar bumpy carpet in the mid intertidal zone. We have seen it both on outer exposed coasts and also in protected inland waters.

Sea Cauliflower occurs epiphytically on articulated coralline algae in many areas along the coast. When corallines were experimentally removed from rocks exposed to abrasion by sand, the Sea Cauliflower was not able to colonize the rock directly. <
BR> Individuals from southern British Columbia/northern Washtington can withstand a week of immersion in water at a temperature of 18°C (64°F) but succumb at higher temperatures.

Source:  North Pacific Seaweeds