Citrus diversity in Roman Naples: pollen evidence for tangerines

The early history of Citrus fruits in the Mediterranean has been an active area of discussion amongst archaeobotanists, historians and palynologists in recent years. It has been well-established that citrons (Citrus medica) and lemons (Citrus limon) were known. For one thing they appear distinctively in Roman art, and for another their seeds are well known from Pompeii (e.g. Celant and Fiorentino 2018). What has been less clear is whether anything that we would call an orange today was known. Despite plausible textual sources, it is always hard to translate ancient terms into botanical species, especially in Citrus fruits that are so variety-rich, prone to both hybridization and frequent somatic mutations. So I have tended to think that some of the few orange-like seeds from Pompeii and from Rome, might just be outliers in the range of variation of early lemons (which are likely to have some pomelo and orange related ancestry in their South Asian origins (see, e.g. Fuller et al 2018). But an important new morphometric investigation of pollen of several Citrus species and archaeological pollen from Oplontis (near Pompeii) seems to have cleared this up. 

Lumaga et al. (2020) in a recent Vegetation History and Archaeobotany article, demonstrate the clear distinction in exine form, especially the cell or lumen size, that differentiates oranges (C. reticulata- the more primitive species, or less hybridized, of mandarin oranges or tangerines and similar small, sweet fruits). Much larger lumens characterize lemons. So I stand corrected on the Citrus diversity of Roman Italy: at least citrons, lemons and mandarins were grown.

This raises interesting questions about how these got to Rome. While these oranges were certainly known in China prior to the Han Dynasty, I have previously deduced that early orange in India-- known from Prakrit and Pali sources of the First Millennium BC-- naranga-- were perhaps most likely bitter oranges (Citrus aurantium), with sweet fruits coming later. Long distance transport of fruits from China to Rome strikes me as unlikely, so perhaps then there was more fruit diversity in northern Indian after all included under the rubrice of naranga, or other less obvious terms. Early South Dravidian languages (precursor to Old Tamil and Kannada) do seem to have two different kinds of oranges. This highlights all the more need for archaeobotanical investigations of early citrus (hidden in flots as charred rind fragments) throughout South Asia and Middle East in the Iron Age period.

I was recently interviewed about the history of Citrus fruits, especially oranges, in Europe in relation to how we can understand their use and symbolism in the writings of William Shakespeare: find the podcast here: That Shakespeare Life.