▁ ▁Hy brid ▁spe ci ation ▁can ▁lead ▁to ▁unclear ▁species ▁boundaries ▁through ▁a ▁process ▁of ▁ret ic ulate ▁evolution , ▁in ▁which ▁species ▁have ▁two ▁parent ▁species ▁as ▁their ▁most ▁recent ▁common ▁ancest ors . ▁In ▁such ▁cases , ▁the ▁hy brid ▁species ▁may ▁have ▁intermediate ▁characters , ▁such ▁as ▁in ▁Hel icon ius ▁but ter f lies . ▁Hy brid ▁spe ci ation ▁has ▁been ▁observed ▁in ▁various ▁species ▁complex es , ▁such ▁as ▁insect s , ▁fung i ▁and ▁plants . ▁In ▁plants , ▁hy brid ization ▁often ▁takes ▁place ▁through ▁pol yp lo id ization , ▁and ▁hy brid ▁plant ▁species ▁are ▁called ▁not hos pecies . ▁ ▁Range ▁and ▁habit ats ▁ ▁S ources ▁differ ▁on ▁whether ▁or ▁not ▁members ▁of ▁a ▁species ▁group ▁share ▁a ▁range . ▁A ▁source ▁from ▁Iowa ▁State ▁University ▁Department ▁of ▁Agr onomy ▁states ▁that ▁members ▁of ▁a ▁species ▁group ▁usually ▁have ▁partially ▁over la pping ▁ranges ▁but ▁do ▁not ▁inter bre ed ▁with ▁one ▁another . ▁A ▁Dictionary ▁of ▁Zo ology ▁( O x ford ▁University ▁Press ▁ 1 9 9 9 ) ▁describes ▁a ▁species ▁group ▁as ▁complex ▁of ▁related ▁species ▁that ▁exist ▁al lop atr ically ▁and ▁explains ▁that ▁the ▁" group ing ▁can ▁often ▁be ▁supported ▁by ▁experimental ▁cross es ▁in ▁which ▁only ▁certain ▁pairs ▁of ▁species ▁will ▁produce ▁hy br ids ." ▁The ▁examples ▁given ▁below ▁may ▁support ▁both ▁uses ▁of ▁the ▁term ▁" species ▁group ." ▁ ▁O ften , ▁such ▁complex es ▁do ▁not ▁become ▁evident