Zelkova is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of six species of deciduous

Deciduous

Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...

 tree

Tree

A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

s in the elm family Ulmaceae

Ulmaceae

Ulmaceae is a family of flowering plant that includes the elms , and the zelkovas . Members of the family are widely distributed throughout the north temperate zone, and have a scattered distribution elsewhere except for Australasia.The family was formerly sometimes treated to include the...

, native to southern Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, and southwest and eastern Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

. They vary in size from shrub

Shrub

A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

s (Z. sicula) to large trees up to 35 m tall (Z. carpinifolia). The leaves

Leaf

A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

 are alternate, with serrated margins, and (unlike the related elm

Elm

Elms are deciduous and semi-deciduous trees comprising the genus Ulmus in the plant family Ulmaceae. The dozens of species are found in temperate and tropical-montane regions of North America and Eurasia, ranging southward into Indonesia. Elms are components of many kinds of natural forests...

s) a symmetrical base to the leaf blade. The fruit

Fruit

In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...

 is a dry, nut

Nut (fruit)

A nut is a hard-shelled fruit of some plants having an indehiscent seed. While a wide variety of dried seeds and fruits are called nuts in English, only a certain number of them are considered by biologists to be true nuts...

-like drupe

Drupe

In botany, a drupe is a fruit in which an outer fleshy part surrounds a shell of hardened endocarp with a seed inside. These fruits develop from a single carpel, and mostly from flowers with superior ovaries...

, produced singly in the leaf axils.

• Zelkova abelicea
  Zelkova abelicea
  Zelkova abelicea, also known as Cretan zelkova, is a species that belongs to the genus Zelkova and is endemic to the Greek island of Crete. It is found in small numbers and is classified as Vulnerable on the IUCN red list of endangered species....
  
  — Cretan Zelkova (Crete in Greece)
• Zelkova carpinifolia
  Zelkova carpinifolia
  Zelkova carpinifolia is a species of Zelkova, native to the Caucasus, Kaçkar, and Alborz mountains in the extreme southeast of Europe and southwest Asia....
  
  — Caucasian Zelkova (Turkey, Georgia, Armenia, Azerbaijan, Iran)
• Zelkova serrata
  Zelkova serrata
  Zelkova serrata is a species of Zelkova native to Japan, Korea, eastern China, and Taiwan. It is often grown as an ornamental tree, and used in bonsai.-Description:...
  
  — Keyaki or Japanese Zelkova (Japan, Korea, Kuril Islands in Russia, Taiwan, China)
  • Zelkova serrata var.