Heterophylly is where a plant has at least two different types of leaves. The differences may be in shape or size of the leaves. A particularly dramatic example of a heterophyllous plant is ''

Ranunculus aquatilis ''Ranunculus aquatilis'', the common water-crowfoot or white water-crowfoot, is a plant species of the genus ''Ranunculus'', native throughout most of Europe and western North America, and also northwest Africa. This is an aquatic plant Aquat ...

''. It, like many aquatic plants, develops two very distinctive leaf types in response to the top of the plant being exposed to air. Underwater the leaves are very divided into thin strands while at or above the water surface it produces a wide, only partly divided, leaf blade. The first use in English was in 1874 by

Robert Brown Robert Brown may refer to: Robert Brown (born 1965), British Director, Animator and author Entertainers and artists * Washboard Sam or Robert Brown (1910–1966), American musician and singer * Robert W. Brown (1917–2009), American printmaker ...

in his ''A Manuel of Botany''. There he defined it as, "variation in the external form of leaves". Heterophylly is a compound word "hetero-" from the Greek ἕτερος meaning different combined with "-phylly" from Greek φύλλον meaning leaf. Heterophylly may be subdivided into different types, such as foliar dimorphism, heterophylly between different kinds of shoots, heteroblasty, and anisophylly. In foliar dimorphism there are distinct juvenile and adult forms of leaves. An example of this are the adult and juvenile leaves of the ''

Eucalyptus ''Eucalyptus'' () is a genus of more than 700 species of flowering plants in the family Myrtaceae. Most species of ''Eucalyptus'' are trees, often Mallee (habit), mallees, and a few are shrubs. Along with several other genera in the tribe Eucalyp ...

'' trees. The juvenile leaves are usually attached on opposite sides of a shoot directly to it while the adult leaves are attached alternately by short leaf stems. A heterophyllous plant may have different kinds of leaves on different parts. For example in the redwood family,

Cupressaceae Cupressaceae or the cypress family is a family of conifers. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdioecious or (rarely) dioecio ...

, the leading shoots often have a different leaf type than those on side shoots.

Heteroblasty Heteroblasty is the significant and abrupt change in form and function, that occurs over the lifespan of certain plants. Characteristics affected include internode length and stem structure as well as leaf form, size and arrangement. It should no ...

is where the leaves change in form or function along the length of a shoot, branch, or other part. This may be a gradual change along the length of a shoot or it may be an abrupt change such as from a scale like leaf to a photosynthetic one. Plants may also be called heterophyllous if they have different leaves at different times, such as some of the carnivorous butterworts of genus ''

Pinguicula ''Pinguicula'', commonly known as butterworts, is a genus of carnivorous flowering plants in the family Lentibulariaceae. They use sticky, glandular leaves to lure, trap, and digest insects in order to supplement the poor mineral nutrition they ...

'' which have differently adapted leaves for the summer and winter.

References

{{Reflist Leaf morphology 1870s neologisms