Urchins are generally round, but some are flat! Like those we call sand dollars.

When this type of urchin washes up on shore, it loses its spikes when it dies, leaving an elegant, flowerlike silhouette on its back. In reality, these marks are what remains of its gills, the tiny holes through which the urchin breathes.

A great many plants live along shorelines, beaches and sand dunes although the conditions on sandy shores are not very inviting for vegetation.

Many of them, like dune grass, or wild rye, have special mechanisms enabling them to grow in these inhospitable environments.

For example, they may have a better tolerance to high salinity levels, uprooting and dewatering.