<P> Corylus has 14--18 species . The circumscription of species in eastern Asia is disputed, with WCSP and the Flora of China differing in which taxa are accepted; within this region, only those taxa accepted by both sources are listed below . The species are grouped as follows: </P> <Ul> <Li> Nut surrounded by a soft, leafy involucre, multiple - stemmed, suckering shrubs to 12 m tall <Ul> <Li> Involucre short, about the same length as the nut <Ul> <Li> Corylus americana--American hazel, eastern North America </Li> <Li> Corylus avellana--Common hazel, Europe and western Asia </Li> <Li> Corylus heterophylla--Asian hazel, Asia </Li> <Li> Corylus yunnanensis--Yunnan hazel, central and southern China </Li> </Ul> </Li> <Li> Involucre long, twice the length of the nut or more, forming a' beak' <Ul> <Li> Corylus colchica--Colchican filbert, Caucasus </Li> <Li> Corylus cornuta--Beaked hazel, North America </Li> <Li> Corylus maxima--Filbert, southeastern Europe and southwest Asia </Li> <Li> Corylus sieboldiana--Asian beaked hazel, northeastern Asia and Japan (syn. C. mandshurica) </Li> </Ul> </Li> </Ul> </Li> <Li> Nut surrounded by a stiff, spiny involucre, single - stemmed trees to 20--35 m tall <Ul> <Li> Involucre moderately spiny and also with glandular hairs <Ul> <Li> Corylus chinensis--Chinese hazel, western China </Li> <Li> Corylus colurna--Turkish hazel, southeastern Europe and Asia Minor </Li> <Li> Corylus fargesii--Farges' hazel, western China </Li> <Li> Corylus jacquemontii--Jacquemont's hazel, Himalaya </Li> <Li> Corylus wangii--Wang's hazel, southwest China </Li> </Ul> </Li> <Li> Involucre densely spiny, resembling a chestnut burr <Ul> <Li> Corylus ferox--Himalayan hazel, Himalaya, Tibet and southwest China (syn. C. tibetica). </Li> </Ul> </Li> </Ul> </Li> </Ul> <Li> Nut surrounded by a soft, leafy involucre, multiple - stemmed, suckering shrubs to 12 m tall <Ul> <Li> Involucre short, about the same length as the nut <Ul> <Li> Corylus americana--American hazel, eastern North America </Li> <Li> Corylus avellana--Common hazel, Europe and western Asia </Li> <Li> Corylus heterophylla--Asian hazel, Asia </Li> <Li> Corylus yunnanensis--Yunnan hazel, central and southern China </Li> </Ul> </Li> <Li> Involucre long, twice the length of the nut or more, forming a' beak' <Ul> <Li> Corylus colchica--Colchican filbert, Caucasus </Li> <Li> Corylus cornuta--Beaked hazel, North America </Li> <Li> Corylus maxima--Filbert, southeastern Europe and southwest Asia </Li> <Li> Corylus sieboldiana--Asian beaked hazel, northeastern Asia and Japan (syn. C. mandshurica) </Li> </Ul> </Li> </Ul> </Li> <Ul> <Li> Involucre short, about the same length as the nut <Ul> <Li> Corylus americana--American hazel, eastern North America </Li> <Li> Corylus avellana--Common hazel, Europe and western Asia </Li> <Li> Corylus heterophylla--Asian hazel, Asia </Li> <Li> Corylus yunnanensis--Yunnan hazel, central and southern China </Li> </Ul> </Li> <Li> Involucre long, twice the length of the nut or more, forming a' beak' <Ul> <Li> Corylus colchica--Colchican filbert, Caucasus </Li> <Li> Corylus cornuta--Beaked hazel, North America </Li> <Li> Corylus maxima--Filbert, southeastern Europe and southwest Asia </Li> <Li> Corylus sieboldiana--Asian beaked hazel, northeastern Asia and Japan (syn. C. mandshurica) </Li> </Ul> </Li> </Ul>

A deciduous shrub with edible brown nuts a species of hazel