Calligonum 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 plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

s in the family Polygonaceae

Polygonaceae

Polygonaceae is a family of flowering plants known informally as the "knotweed family" or "smartweed family"— "buckwheat family" in the United States. The name is based on the genus Polygonum and was first used by Antoine Laurent de Jussieu in 1789 in his book, Genera Plantarum. The name refers...

 with about 80 species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 around the Mediterranean, 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...

 and in the North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

.

Characteristics

Plants of the Calligonum genus are shrubs, diffusely but irregularly branched, with flexuous woody branches. Leaves are simple, opposite, nearly sessile, linear or scale-like, sometimes absent or very small, linear or filiform, distinct or united with short membranous ochreae. Flowers are bisexual, solitary or in loose axillary inflorescences. Flowers have persistent, 5-parted perianth

Perianth

The term perianth has two similar but separate meanings in botany:* In flowering plants, the perianth are the outer, sterile whorls of a flower...

  not accrescent in fruit. Stamen

Stamen

The stamen is the pollen producing reproductive organ of a flower...

s 12-18, with filaments connate at base. Ovary

Ovary (plants)

In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule and is located above or below or at the point of connection with the base of the petals and sepals...

 is tetragonous.

Systematics

The species include:

• Calligonum aphyllum
• Calligonum arborescens
• Calligonum alaschanicum
• Calligonum calliphysa
• Calligonum caput-medusae
• Calligonum chinense
• Calligonum colubrinum
• Calligonum comosum
• Calligonum cordatum
• Calligonum crinitum
• Calligonum comosum
• Calligonum densum
• Calligonum ebinuricum
• Calligonum gobicum
• Calligonum jeminaicum
• Calligonum junceum
• Calligonum klementzii
• Calligonum korlaense
• Calligonum leucocladum
• Calligonum microcarpum
• Calligonum mongolicum
• Calligonum polygonoides
  Calligonum polygonoides
  Calligonum polygonoides, locally known as Phog , is a small shrub, found in Thar desert areas, usually 4 feet to 6 feet high but occasionally may reach even 10 feet in height with a girth of 1 to 2 ft. This tree is also named orta in old Arabic poems. So much people agree the arabic origin of...
  
  
• Calligonum potanini
• Calligonum pumilum
• Calligonum roborowskii
• Calligonum rouqiangense
• Calligonum rubicundum
• Calligonum squarrosum
• Calligonum trifarium
• Calligonum yengisaricum
• Calligonum zaidamense