▁these ▁organ isms ▁are ▁govern ed ▁by ▁the ▁( IC N ), ▁even ▁today . ▁Some ▁prot ists ▁that ▁do ▁not ▁fit ▁easily ▁into ▁either ▁plant ▁or ▁animal ▁categories ▁are ▁treated ▁under ▁either ▁or ▁both ▁of ▁the ▁I CN ▁and ▁the ▁IC Z N . ▁A ▁separate ▁Code ▁was ▁adopted ▁to ▁govern ▁the ▁nom en cl ature ▁of ▁B acter ia , ▁the ▁International ▁Code ▁of ▁N omen cl ature ▁of ▁B acter ia . ▁ ▁Rel ations hip ▁to ▁tax onomy ▁ ▁Botan ical ▁nom en cl ature ▁is ▁closely ▁linked ▁to ▁plant ▁tax onomy , ▁and ▁botan ical ▁nom en cl ature ▁serves ▁plant ▁tax onomy , ▁but ▁never theless ▁botan ical ▁nom en cl ature ▁is ▁separate ▁from ▁plant ▁tax onomy . ▁Botan ical ▁nom en cl ature ▁is ▁merely ▁the ▁body ▁of ▁rules ▁pres cri bing ▁which ▁name ▁applies ▁to ▁that ▁tax on ▁( see ▁correct ▁name ) ▁and ▁if ▁a ▁new ▁name ▁may ▁( or ▁must ) ▁be ▁co ined . ▁ ▁Plant ▁tax onomy ▁is ▁an ▁empir ical ▁science , ▁a ▁science ▁that ▁determ ines ▁what ▁constit utes ▁a ▁particular ▁tax on ▁( tax onom ic ▁grouping , ▁pl ural : ▁tax a ): ▁e . g . ▁" What ▁plants ▁belong ▁to ▁this ▁species ?" ▁and ▁" What ▁species ▁belong ▁to ▁this ▁genus ? ". ▁The ▁definition ▁of ▁the ▁limits ▁of ▁a ▁tax on ▁is ▁called ▁its ▁' circ ums cription '. ▁For ▁a ▁particular ▁tax on , ▁if ▁two ▁tax onom ists ▁agree ▁exactly ▁on