You selected Arnica caudata Rydb. This is a synonym for:

Accepted scientific name:
Arnica longifolia D.C.Eaton (provisionally accepted name)
Synonyms:
Arnica caudata Rydb. (synonym)
Arnica myriadenia Piper (synonym)
Arnica polycephala A.Nelson (synonym)
Common names: -
Classification:
Plantae
Phylum Magnoliophyta
Class Magnoliopsida
Order Asterales
Family Asteraceae
Genus Arnica
Distribution: -
Additional data: Data Providers: Govaerts World Compositae Checklist A-G, IPNI, Tropicos, LCR Editor, Preliminary Checklist of North American Compositae. GCC LSID: urn:lsid:compositae.org:names:C17F92B9-381C-4F2F-9C96-A30FFFB5A1DA
Source database: GCC, 2 (Beta), Nov 2010
Latest taxonomic scrutiny: Flann C., 01-Nov-2010
Online resource: http://compositae.landcareresearch.co.nz/default.aspx?Page=NameDetails&TabNum=0&NameId=C17F92B9-381C-4F2F-9C96-A30FFFB5A1DA
CoL taxon LSID: urn:lsid:catalogueoflife.org:taxon:cfffbb72-2dc5-11e0-98c6-2ce70255a436:col20110201