Although called navelwort (Umbilicus rupestris) in my main field guide it is known as wall pennywort in some others. Another example of the confusion common names and local variations can bring.
Navelwort is a member of the stonecrop family, otherwise known in botanical circles as crassulaceae, and like its relatives is usually found growing on walls, often by the sea, and can also be found on rocks where the sea does reach high enough in storms to wash it off. It does also grow on earth banks some times. It is quite a distinctive plant growing in a spike which can vary from 6 inches to one foot six inches depending on its location but I suppose 9 inches is about normal. It is a perennial plant and has fleshy leaves to store moisture when it can get it so that it can avoid drying out in spells without rain. The flowers are an off-white colour and are bell shaped. They grow and dangle from the central stem a bit like a foxglove! The stem is often a reddish brown.
Why the peculiar name of navelwort? Apparently it comes from the leaves which are round with a dimple in the middle. It is thought to have many healing properties and seems to cure just about every ailment you could possibly pick up.