Papillate Seaweed/Sea Tar (Mastocarpus papillatus) grows in two stages. The crustose phase pictured here reproduces asexually to produce spores that grow into the blade stage. In the crustose phase the plant grows very slowly, about 1/2 inch per year, meaning that some large specimens could be nearly 100 years old. Range is from the Aleutian Islands to South America. Photographed at Coal Oil Point, Santa Barbara County, California.