Boxthorn

Boxthorn (Lycium) is a genus (tribe Lycieae, family Solanaceae) of about 90 species of plants native throughout much of the subtropical zones of the world, mostly found in dry, semi-saline environments.

Common names include wolfberry, desert-thorn, Christmas berry, Matrimony vine, and the confusing "Tea-tree" (it is not related to tea, and with the foliage being toxic, should not be used as such). Goji is a common English name made popular by several American-made juices and dried berries sometimes branded as "Tibetan" or "Himalayan" goji berries, although these terms do not geographically represent where the berries actually originate.

There are ~20 species in North America, ~30 species in South America, ~30 species in Africa, ~10 species in Eurasia, and one species in Australia. Grabowskia and Phrodus join Lycium in tribe Lycieae, and are the genera most closely related to Lycium.

They are long-lived, perennial, thorny shrubs, with deciduous alternate, simple leaves 1-8 cm long. The flowers are solitary or in small clusters, 6-25 mm diameter, with a corolla of five purple, white or greenish-white petals joined together at their bases. The fruit is fleshy, multiseeded berry 8-20 mm diameter that may be red, yellow, orange, purple or black. These fruit resemble nightshade and bittersweet berries. In some species, notably L. barbarum (Wolfberry), the fruit is edible (see that species for further detail).

Most species of Lycium are cosexual (all flowers have both male and female function), however, several species exhibit gender dimorphism. Evidence suggests that sexual dimorphism has evolved more than once in the Lycium genus. There are species that have both monecious and dioceous populations, most notably L. californicum.

The plant has been known to European herbalists since ancient times. In his Naturalis historia, Pliny the Elder describes Lycium as a medicinal plant (recommended as a treatment for sore eyes and inflammation), as does Pedanius Dioscorides in his P. Dioscoridae pharmacorum simplicium reique medicae (Hitchcock 1932). In his 1753 publication Species Plantarum, Linnaeus describes three Lycium species: L. afrum, L. barbarum, and L. europaeum (Hitchcock 1932).

Uses
The fruit, leaves, and bark of certain species have been used in China throughout more than 2,000 years of recorded history. The fruit is known in China as gouqizi (枸杞子, wolfberry, Lycium barbarum), where it is used in herbal teas, soups, juices, and alcoholic beverages.

The berries may also be eaten whole and are used in this way for a variety of purposes in traditional Chinese medicine, as well as traditional Korean medicine, traditional Japanese medicine, and traditional Tibetan medicine.

The berry has a complex, rich nutrient and phytochemical profile among which its active ingredients include multiple essential vitamins, minerals, sources of dietary fiber, protein and numerous carotenoids, polyphenols, and polysaccharides (Gross et al., 2006).

Lycium species are used as food plants by the larvae of some Lepidoptera species including Coleophora vigilis (recorded on L. ferocissimum).