Systematics of the economically important genus Elaeagia in the coffe family (Rubiaceae)

Rubiaceae are one of the largest families of flowering plants with approximately 650 genera and 13,000 species worldwide, and about 220 genera and 5,000 species in the Neotropics. Many Rubiaceae are economically important including coffee (Coffea arabica) and the Quina tree (Cinchona succiruba, C. lancifolia) whose bark contains alkaloids that are used to cure malaria. The family also include many ornamental plants such as the much appreciated Gardenias (Gardenia jasminoides). Considering its economic importance, the systematic classification and evolution of this family has received remarkably little attention compared to other large families like the Asteraceae and the Orchidaceae.

Elaeagia Weddell is a relatively small New World genus of Rubiaceae that includes around 15 species. It comprises small to medium size trees in tropical mountains mainly between 500 m and 1500 m elevation. Elaeagia differs from all other Rubiaceae by secreting a greenish resin from the stipules of the foliar buds. This resin is known as “lacquer” and has the appearance of small, sticky pellets that may be handpicked from the young shoots of the trees. From immemorial times, artisans in San Juan de Pasto, Nariño-Colombia, have applied a specialized technique covering their famous handicrafts with the “lacquer” resin of Elaeagia pastoense L. E. Mora, known as “Barniz de Pasto.” In order to obtain “Barniz de Pasto,” the artisans first heat the resin balls to form a malleable mass. Afterwards, the resin is stretched and cleaned, and may be coloured. The resin is manipulated until a very thin, sticky layer is formed, and this is spread at the surface of the material the artisan is working with, which could be wood, metal or glass. Overall this treatment corresponds to wrapping handicrafts with a coloured “cloth” that gives them a truly attractive appearance.

Elaeagia occur in most mountain forests in the Americas. It ranges from southern Mexico, through Central America, along the Andes south to Bolivia. It is also found at a number of West Indian islands including Cuba. Botanists have described more than 20 different species of Elaeagia, but the true number is unknown, and can only be determined by studying and comparing collections from all parts of its range. Fortunately, the number of Elaeagia collections has risen steadily during recent decades facilitating that this work now can be done.

The objective of the present project is to elaborate a detailed taxonomic and phylogenetic study of the genus Elaeagia. This study should help to determine if other species of Elaeagia show similar properties as E. pastoense, and consequently may be used in similar ways. The uses of E. pastoense and other Elaeagia species will be valued economically, socially and ecologically.

Participant Carla Maldonado, supervised by Finn Borchsenius, Henrik Balslev & Mónica Moraes