Equisetum horse tail spore (Equisetum arvense) Science Image

Ref: 80200211a



Horsetail spore. Coloured scanning electron micrograph (SEM) of a spore of a horsetail (Equisetum arvense) plant. Spores (round) bear elaters (helical), which expand and contract with changes in humidity. Elaters help to tangle spores together into a clump called a propagule, and to dig the spores into the soil. Magnification: x370 when printed 10 centimetres wide.