They are perennial plants , either herbaceous and dying back in winter as most temperate species , or evergreen as most tropical species and the temperate species Rough Horsetail -LRB- E. hyemale -RRB- , Branched Horsetail -LRB- E. ramosissimum -RRB- , Dwarf Horsetail -LRB- E. scirpoides -RRB- and Variegated Horsetail -LRB- E. variegatum -RRB- .

They are perennial plants , either herbaceous , they back in winter -LRB- most temperate species -RRB- or they are evergreen -LRB- some tropical species , and the temperate species MISC@1 hyemale , E. scirpoides , E. variegatum and E. ramosissimum -RRB- .
