Horsetail and Horse tail

Horsetail noun - Perennial rushlike flowerless herbs with jointed hollow stems and narrow toothlike leaves that spread by creeping rhizomes; tend to become weedy; common in northern hemisphere; some in Africa and South America.

Horse tail and horsetail are semantically related. In some cases you can replace phrase "Horse tail" with "Horsetail", this terms are similar.

Horsetail and horse tail are semantically related. You can use "Horsetail" instead a noun phrase "Horse tail".