▁only ▁by ▁the ▁Or ch id aceae . ▁Which ▁of ▁the ▁two ▁families ▁actually ▁is ▁the ▁larger ▁is ▁unclear , ▁because ▁of ▁the ▁uncertainty ▁about ▁how ▁many ▁ext ant ▁species ▁each ▁family ▁includes . ▁▁ ▁Near ly ▁all ▁A ster aceae ▁bear ▁their ▁flowers ▁in ▁dense ▁heads ▁( cap it ula ▁or ▁pseud anth ia ) ▁surrounded ▁by ▁invol uc ral ▁b ract s . ▁When ▁viewed ▁from ▁a ▁distance , ▁each ▁capit ul um ▁may ▁have ▁the ▁appearance ▁of ▁being ▁a ▁single ▁flower . ▁En larg ed ▁outer ▁( per i pher al ) ▁flowers ▁in ▁the ▁capit ula ▁may ▁res emble ▁pet als , ▁and ▁the ▁invol uc ral ▁b ract s ▁may ▁look ▁like ▁a ▁cal y x . ▁The ▁name ▁A ster aceae ▁comes ▁from ▁the ▁type ▁genus ▁A ster , ▁from ▁the ▁An cient ▁Greek ▁, ▁meaning ▁star , ▁and ▁refers ▁to ▁the ▁star - like ▁form ▁of ▁the ▁ ▁infl ores c ence . ▁Compos ita e ▁is ▁an ▁older ▁( but ▁still ▁valid ) ▁name ▁that ▁refers ▁to ▁the ▁" compos ite " ▁nature ▁of ▁the ▁capit ula , ▁which ▁consist ▁of ▁( f ew ▁to ) ▁many ▁individual ▁flowers . ▁▁ ▁Most ▁members ▁of ▁A ster aceae ▁are ▁annual ▁or ▁per enn ial ▁her bs , ▁but ▁a ▁significant ▁number ▁are ▁also ▁shr ubs , ▁v ines , ▁or ▁trees . ▁The ▁family ▁has ▁a ▁cosm opol itan ▁distribution , ▁with ▁species ▁r anging ▁from ▁sub pol ar ▁to ▁tropical ▁regions , ▁colon izing ▁a