Plant 99

Smilax asper L. (Smilacaceae)



The genus Smilax comprises about 300 species of mostly climbing plants distributed across both world's temperate and tropical regions. Members of the genus can be woody lianes or, in North America, herbaceous climbers. Individuals are either male or female, bearing inconspicuous flowers in umbels; the female plants produce berries. Formerly included in the monocot family Liliaceae, Smilax is now part of the family Smilacaceae, which also includes the genus Heterosmilax. The two families are distinguished by anatomical differences in the water-conducting tissues and the net venation, rather than parallel venation, of Smilacaceae leaves. Smilax is unique amongst angiosperms in having stipules which are modified as tendrils. It is also atypical of other monocots in having a pair of stipules rather than a single stipule.

The name Smilax comes from the Ancient Greek for bindweed. Many Smilax species have recurved hooks on the stems which make them effective climbers; they must be handled with considerable care. Smilax aspera is no exception; the stems are covered in sharp hooks which also extend along the underside of the midribs of the dark green, leathery leaves. Smilax aspera is an evergreen, perennial scrambler reaching a height of three metres in woodland or scrub habitats. This species is widely distributed across the Mediterranean, Central Africa and parts of both temperate and tropical Asia. Furthermore, greenbrier is morphologically variable. Female plants produce clusters of small, one- to three-seeded fruits which ripen from red to black; the seeds are bird dispersed.

Although we do not eat the fruits, other plant parts, including the rhizomes (horizontal underground stems), of many Smilax species are edible. The soft drink sarsaparilla has traditionally been made from the rhizome of tropical Smilax species, historically mixed with the bark of the lauraceous tree Sassafras. Popular in the United States since the nineteenth century, sarsaparilla was thought to prevent sexually transmitted diseases and be a tonic for athletes. The drink has become globally popular, although today artificial flavourings often replace the Smilax rhizome extract. In India, a Smilax species is used to make the drink Nannari Sherbet and is included in the Ayurvedic pharmacopeia. Often, the rhizomes of Smilax are rich sources of carbohydrate and of vitamin C. Shoots of Smilax aspera have been cooked and eaten in the manner of asparagus, whilst a red dye has been extracted from the tendrils. Ripe fruits have also been applied to the skin to alleviate scabies.

Further reading

Bell A (2008) Plant form: an illustrated guide to flowering plant morphology. Timber Press.

Manandhar NP (2002) Plants and people of Nepal. Timber Press.

James Penny