Spinulum annotinum is a common and widespread club-moss spreading by means of horizontal stems running along the surface of the ground. It is usually unbranched or sparingly branched, each branch containing a cone at the top. Leaves have minute teeth on their edges.[
Requires a humid atmosphere. Terrestrial members of this genus are hard to establish. The roots are delicate and liable to rot, most water being absorbed through the foliage.
He plant has been mixed with potting compost to act as a fertilizer and make plants growing in it healthier
The plant contains lycopodine, which is poisonous by paralysing the motor nerves[21, 218]. It also contains clavatine which is toxic to many mammals[218]. The spores, however, are not toxic[21].