In western cultures, the deep-red resin dragon's blood has been an exotic ingredient of traditional medicines and dyes since ancient times. The resin, a dried exudate, is extracted from different species in different parts of the world; sources include members of the Euphorbiaceae, Fabaceae and Arecaceae. However, the most famous sources are two Dracaena species: Socotran dragon's blood (Dracaena cinnabari) and Canary Island dragon's blood (Dracaena draco).
Dracaena draco, whose scientific name reinforces its association with dragons, is a combination of the Greek 'she-dragon' and 'dragon'. It is native to Macaronesia (Madeira, Canary Islands, Cape Verde) and Morocco, where natural populations are frequently small, and under threat from humans hence the dragon tree is considered Vulnerable. However, the dragon tree is very widely cultivated for its form, curiosity and symbolic value. The first reports of dragon trees in the Canary Islands came from Jean de Bethencourt's expedition in 1402.
The genus Dracaena contains about 120 species. Most species are found in wet and dry forests of the Old World tropics, with outliers in Micronesia and Macaronesia, the Caribbean and Central America. The discovery of a 16 million-year-old fossil Dracaena from Anatolia, with features allied to the xerophyte Dracaena draco, has been used to suggest modern dragon trees may have evolved from wet-forest species.
The dragon tree has a very distinctive growth form. Young trees have single stems and are topped by a dense crown of long, sword-shaped leaves. After about a decade, the first white, lily-like flowers and red fruits are produced. A crown of terminal buds is formed and the plant starts to branch. The branches grow for about another decade, flower and branch again. Repetition of the process over time produces a tree with a hemispherical crown. Branches also produce aerial roots which grow down to the soil, contributing to the bulk of old trees.
Individual dragon trees live to immense ages. When the Prussian naturalist and biogeographer Alexander von Humboldt visited Tenerife in 1799, on his way to South America, he saw a dragon tree at Oratava which he measured as over 21 metres tall and nearly five metres in diameter. The tree was venerated by the Guanche and Humboldt estimated its age as about 6,000 years old; the plant was lost in a storm in 1868. Today, the oldest living specimen on the island is at Icod, although it is probably only about 400 years old.
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Denk T et al 2014. From mesic to arid: Leaf epidermal features suggest preadaptation in Miocene dragon trees (Dracaena). Review of Palaeobotany and Palynology 200: 211-228.
Symon DE 1974. The growth of Dracaena draco - dragon's blood tree. Journal of the Arnold Arboreum 55: 51-58.