If you look into a tidepool at very low tide, when the water has receded away, and the sand has become muck, you might find velvety mossy-green blobs. Almost like pincushions or velcro, they may have collected little bits of shells, broken sand dollars, and crushed barnacles. But as more water comes into the tidepool, these green blobs open into one of the most beautiful animals you can see along the shoreline: anemones.
Flower-like aggregating anemones wave tentacles that seem like they are surrounded by tiny pearls. These appendages search for small crustaceans that happen by in the currents of the pool. The anemones also get nutrition from algae living within them. These symbiotic plants give them their vibrant green color.
Often in a tidepool, there will be many anemones clustered, or aggregated together. They are all part of one family tree. An original anemone can clone itself, dividing many times to create an aggregation of creatures. But two clone sets never touch. After learning this fact, I am eager to return to tidepools and find two different clone groups of anemones and discover the dividing border--almost like two anemone nations or two opposing teams.
One of the most wonderful things about tidepooling is that it is one of the most accessible ways to see marine animals up close--while still staying on dry land. The key is to look up low tide times for whatever beach you are visiting. As tides recede, they reveal the world of intertidal creatures. Aggregating anemones live from Southern California to Alaska, and I was excited to see my first anemones in Oregon recently (having much more experience tidepooling in California).
According to the excellent reference, Seashore: Northern and Central California, anemones survive best in protected tidepools away from pounding waves. Remember that in pools not full of water, they look like green blobs, and when the tide flows in, they send out tentacles in search of prey.
For me, I like the way that anemones bridge the feeling of plant and animal. While clearly an animal, they sway in the water the way that a tree moves in the wind. Algae, tiny plants, give them their green color.