The squishy one has fronds that are soft. They are inflated sacs. Like small, golden-brown pillows or water balloons. Adenocystis utricularis is filled with a gelatinous, jelly-like substance. Not air. When you touch them, they feel soft and squishy. They yield to your fingers. They look like they might burst. But they are tougher than they seem. It is the alga of the soft touch. The one that gives when you press it. What makes it special is the texture. The spongy kelp is soft and gelatinous. Unlike the tough, leathery fronds of other kelps. The jelly inside the sacs is a mixture of water and polysaccharides. It helps the plant retain moisture at low tide. It also makes the plant less appealing to grazing animals. Snails and sea urchins prefer tougher, more substantial fare. It is the alga of the clever defence. The one that protects itself by being unappetising. The fronds are club-shaped or pear-shaped. They taper to a narrow stem. They are usually five to fifteen centimetres long. Pale golden-brown to olive-green. They grow in clusters. Attached to the rock by a small, disc-like holdfast. Under a hand lens, the surface is smooth and shiny. With a gelatinous sheen. Biologically, the spongy kelp is a brown alga. It reproduces by releasing spores from specialised structures on its fronds. The spores are released into the water. Carried by the currents. They settle on nearby rocks to grow into new plants. To find spongy kelp is to find a patch of soft, squishy pillows on the rock. They look like they might pop if you poke them. But they do not. They are soft. Yielding. Almost friendly. It is the squishy one. The gelatinous one. The one that looks like it might burst but never does. The one that proves that softness can be a form of strength. No recorded Māori name distinguishes the spongy kelp from other brown seaweeds. It was likely grouped with other brown seaweeds called rimu. The soft, gelatinous texture would have been noticed. It was different from the tough, leathery kelps of the exposed coast. It was a seaweed that yielded to the touch. That squished between the fingers. The spongy kelp was sometimes used as a poultice. The jelly inside the sacs was applied to wounds and skin infections to soothe and heal. It was a gentle medicine from the sea.