Achachairu in Australia

Achahairu is a plant native to tropical south and central America that is included in the genus Garcinia in the Clusiaceae family. Historically the taxonomy of this genus has been a difficult and inadequately studied problem as it includes many species with overlapping and often insufficiently different morphological features that would allow clear species delineation using classical techniques. The problem has been compounded more recently with inclusion of a number of other genera, but it’s hoped that use of modern molecular techniques will help resolve the area. The USDA currently lists 72 species in the genus globally, but most of these are from outside the neotropics and some are synonyms. It's also likely among the smaller number of currently-listed neotropical species that many of these are actually edpaho-climatic variants of individual species and don’t warrant individual status. For example, a recent molecular genetic study in Colombia concluded there were only six native species in that country that were justified as separate and distinct.

An early name for achachairu was Rheedia laterifolia, but there is now fairly general agreement that Rheedia species should be renamed and moved into Garcinia. The USDA lists G. humilis as a synonym for R. lateriflora, and G. gardneriana as a synonym for R. laterifolia. The Missouri Botanic Gardens have suggested (2017) that fruit available in Australia originally sourced from Bolivia and called 'achacha' is probably G. gardneriana (achacha was the common name chosen here for marketing reasons instead of the sth American name achachairu). They also suggest that G. brasiliensis is a synonym for G. gardneriana. I was unable to find (as of Mar 2019) any molecular study published in the last 10 years that could help resolve this confusion, so we’re left with a number of names that are synonyms for achachairu.

The convention in taxonomy is that the most recent and properly approved name should be used with earlier ones being superseded, but in the real world, habits can die slowly and we often see older names still being used. While common names can be confusing and misleading, especially across languages and countries, nailing down binomials is important because we need to know when sourcing information whether it's applicable to the plants we have - will they grow into big trees, need cross-pollination, can we cross-graft etc. Obviously the sooner we have a thorough genetic study the better we'll all be. In the meantime however we can speculate that the Australian sourced plants are G gardneriana and this is a synonym for R. laterifolia, so the south American species and what we have here may be identical ie G. gardneriana. There is a taxonomic key for this species, so when we get it to flower and fruit for us we may be able to firm up the hypothesis.

Images/Stars Spacer. LitchiLogo