Pteridophyta/Equisetum

Horstails

Some useful Links:

http://en.wikipedia.org/wiki/Equisetum

http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=111897

http://images.google.co.in/images?q=Equisetum&oe=utf-8&rls=com.ubuntu:en-GB:unofficial&client=firefox-a&um=1&ie=UTF-8&ei=EEGZStTPH4qG6wOYxa3CBA&sa=X&oi=image_result_group&ct=title&resnum=4

http://encyclopedia.farlex.com/Equisetum

http://members.eunet.at/m.matus/