Heather Angel / Broomrape (Pedicularis longiflora) in wet meadow amongst Horsetail (Equisetum sp). Maroon marks on flowers act as Nectar guides. Road from Barkham to Ruo Er Gai, Sichuan Province, China. July.

SCOTLAND: The Big Picture / Eurasian beaver (Castor fiber) swimming across forest lochan with horsetail (Equisetum sp) in mouth, Knapdale Forest, Argyll, Scotland, UK, June.

Alex Hyde / Raft Spider (Dolomedes fimbriatus) female resting on the surface of a moorland pool among stems of Horsetail (Equisetum sp.). Nordtirol, Austrian Alps, June.

Jan Hamrsky / Water scavenger beetle larva (Hydrophilidae) on Horsetail (Equisetum sp) Europe, May. Controlled conditions.

Jan Hamrsky / Case-building caddisfly larva (Triaenodes bicolor) on Horsetail (Equisetum sp), Europe, May. Controlled conditions.

Jan Hamrsky / Silver sedge caddisfly larva (Odontocerum albicorne) on Horsetail (Equisetum sp) Europe, May. Controlled conditions.

Jan Hamrsky / Silver sedge caddisfly larva (Odontocerum albicorne) on Horsetail (Equisetum sp) Europe, May. Controlled conditions.

Ernie Janes / Five bar farm gate with Bird foot trefoil (Lotus corniculatus), Bramble (Rubus sp) and Horsetails (Equisetum) Norfolk, England, UK. July.

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

Piotr Naskrecki / Water Horsetail (Equisetum fluviatile) young shoot with water drops

Piotr Naskrecki / Water Horsetail (Equisetum fluviatile) stem and cone, Estabrook Woods, Massachusetts

Piotr Naskrecki / Field Horsetail (Equisetum arvense) releasing sporophytes, Estabrook Woods, Massachusetts

David Kjaer / Southern Marsh orchid (Dactylorhiza praetermissa) flowering in a wild flower meadow with Horsetails (Equisetum sp), England, UK.

John Cancalosi / Fossilized Horsetail {Equisetum sp} Italy

David Welling / Horsetails (Equisetum sp) Del Norte Redwoods SP, California

Christian Ziegler / Horsetail (Equisetum sp) stand in a swamp, Jasmund National Park, Ruegen, Germany

Christian Ziegler / Horsetail (Equisetum sp) close-up detail, Jasmund National Park, Ruegen, Germany

Christian Ziegler / Horsetail (Equisetum sp) stand in a swamp, Jasmund National Park, Ruegen, Germany

Michio Hoshino / Bearberry (Arctostaphylos uva ursi), Blueberry (Vaccinium sp), and Horsetail (Equisetum sp) in trundra, Alaska

Gerry Ellis / Field Horsetail (Equisetum arvense), Pacific coast, North America

Gerry Ellis / Field Horsetail (Equisetum arvense) among other various vegetation, Pacific coast, North America

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

Piotr Naskrecki / Field Horsetail (Equisetum arvense) stems topped with spore-producing strobilus, Estabrook Woods, Massachusetts