COMMON CLUB MOSS, LYCOPODIUM CLAVATUM Like Irish Moss, which is a sea weed, Common Club Moss is not really a moss but is related to the ferns such as maidenhair and horsetail which it resembles a little. It bears no visual resemblance to the larger common fern, bracken. This common moss grows all over the world and is a common sight in damp woodlands in Britain
Prior to the 17th century the whole plant was used in medicinal preparations, despite its being poisonous. It was used in decoctions to aid digestion and soothe the stomach to get rid of flatulence and was called Muscus terrestris or Muscus clavatum, meaning musk of the earth or musk claw. Lycopodium means wolf’s foot and clavatum, claw. The plant was harvested and dried for medicinal purposes, but it contains lycopodine which is poisonous and paralyses the motor nerves while the substance clavatine also present in the plant is toxic to many mammals; deer, for example do not eat club moss. The decoctions of the plant have been used to help get rid of calculus which builds up around the joints causing inflammation, so it was used for arthritis and rheumatism, as well as gout. It had a reputation for being good for the kidneys.
In the 17th century it was harvested and used only for its spores which are not poisonous, and these have been used as talcum powder, to stop things sticking together, as a dusting powder, to dress moulds in iron foundries and the stems of the plant when dried have been woven into matting. The spores are also used in fireworks and to produce the effect of artificial lightning. 
The spores are shaken from the kidney-shaped capsules (sporangia) which are found on the inner sides of the bracts which cover the fruit spike of club moss, and are a yellow powder. They have been used on injuries as they absorb fluids which exude from wounded tissue. They have diuretic qualities and can help in cases of chronic diarrhoea and dysentery. They would also appear to have some antispasmodic actions. A decoction of the spores has been used to give relief from the pain of gout, rheumatism and arthritis, and for urinary tract disorders and kidney problems. Used externally a decoction can help with skin problems and can stop itching. It is said that if the spores are snuffed up the nose they will stem a nosebleed.
This plant is a very common one, but tricky to harvest so best left to grow in the wild, unless you absolutely know what you are doing.
