2 ▁scheme ▁— ▁above ▁the ▁f used ▁cor ol la ▁t ube , ▁three ▁very ▁long ▁f used ▁pet als ▁form ▁the ▁lig ule , ▁with ▁the ▁other ▁two ▁pet als ▁being ▁incon sp ic u ously ▁small . ▁The ▁C ich orio ide ae ▁has ▁only ▁ray ▁flor ets , ▁with ▁a ▁ 5 + 0 ▁scheme ▁— ▁all ▁five ▁pet als ▁form ▁the ▁lig ule . ▁A ▁ 4 + 1 ▁scheme ▁is ▁found ▁in ▁the ▁Bar n ades io ide ae . ▁The ▁tip ▁of ▁the ▁lig ule ▁is ▁often ▁divided ▁into ▁teeth , ▁each ▁one ▁representing ▁a ▁pet al . ▁Some ▁marg inal ▁flor ets ▁may ▁have ▁no ▁pet als ▁at ▁all ▁( fil iform ▁fl oret ). ▁ ▁The ▁cal y x ▁of ▁the ▁flor ets ▁may ▁be ▁absent , ▁but ▁when ▁present ▁is ▁always ▁modified ▁into ▁a ▁p app us ▁of ▁two ▁or ▁more ▁teeth , ▁scales ▁or ▁br ist les ▁and ▁this ▁is ▁often ▁involved ▁in ▁the ▁disp ersion ▁of ▁the ▁se eds . ▁As ▁with ▁the ▁b ract s , ▁the ▁nature ▁of ▁the ▁p app us ▁is ▁an ▁important ▁di agnostic ▁feature . ▁ ▁There ▁are ▁usually ▁five ▁stam ens . ▁The ▁fil aments ▁are ▁f used ▁to ▁the ▁cor ol la , ▁while ▁the ▁an thers ▁are ▁generally ▁conn ate ▁( s y ng enes ious ▁an thers ), ▁thus ▁forming ▁a ▁sort ▁of ▁t ube ▁around ▁the ▁style ▁( the ca ). ▁They ▁commonly ▁have ▁bas al ▁and / or ▁ap ical