Stephen Dalton / Common horsetail (Equisetum arvense) shedding spores, UK

Jan Hamrsky / Narrow-winged damselfly nymph (Ischnura elegans), camouflaged on a stem of horsetail plant, June, Europe, controlled conditions

Jan Hamrsky / Narrow-winged damselfly nymph (Ischnura elegans), camouflaged on a stem of horsetail plant, June, Europe, controlled conditions

Ross Hoddinott / Blue-tailed damselfly (Ischnura elegans), male on Common horsetail (Equisetum arvense), Cornwall, UK. June.

Ross Hoddinott / Large red damselfly (Pyrrhosoma nymphula) resting on common horsetail, Broxwater, Cornwall, UK. April 2017.

Graham Eaton / Llyn Cwmorthin, with Common horsetail (Equisetum arvense) Tanygrisiau, Wales, February 2014

Dong Lei / Common mare's tail (Hippuris vulgaris) Basongcuo National Park, Qinghai-Tibet Plateau, Tibet, July.

Dong Lei / Common mare's tail (Hippuris vulgaris) Basongcuo National Park, Qinghai-Tibet Plateau, Tibet, July.

Graham Eaton / Common Horsetail (Equisetum arvense) growing on the Llyn Peninsular coast, near Nefyn, North Wales

Bernard Castelein / Field horsetail (Equisetum arvense) fertile shoots, Brasschaat, Belgium, April.

Kevin Schafer / Field Horsetail (Equisetum arvense) plants emerging from shallow water, Moses Coulee, Washington

Alex Hyde / Common horsetail (Equisetum arvense) shedding spores, Peak District National Park, Derbyshire, UK. April.