Early modern Russia sat at the intersection of Eurasian trade networks, which allowed both commodities and information to move from east to west and north to south. Rhubarb exported from China had held a prominent position in Western medical treatments since the classical era, but improved transportation and communication between Europe and Asia through Russia enabled the growth of the medicinal rhubarb trade to unexpected heights after 1760. Earlier studies of rhubarb have focused on European interests in uncovering ‘true’ medicinal rhubarb, but this article will situate the plant as a part of the broader process of scientific exchange across Eurasia. Russia’s unique position in Eurasia ultimately allowed its specialists to contribute to the development of Western science through the importation of information from Asia and its own expeditions in Siberia, Russia’s internal ‘Asian’ territory.

Rhubarb includes approximately 60 species in the genus Rheum. It has been utilized for thousands of years for medicinal purposes, but only recently identified for its culinary use. In the mid 1700s, edible petioles were discovered on seedlings from rhubarb species. Hundreds of cultivars have since been identified for a wide range of uses from tarts to wine. Unfortunately, propagation by seed and irregular naming has resulted in a plethora of similarly named cultivars and multitude of phenotypes. Fifteen morphological characters were evaluated to differentiate rhubarb cultivars in the USDA, ARS Rheum collection in Palmer, Alaska. Two years of morphological data, focusing on horticultural characteristics indicated variation between the years. To improve cultivar resolution, the results suggest using 1 year's data instead of combining data from different years. The mean °Brix observed was 3.8, with a range from 2.2 to 6.1. Flesh colour and basal skin colour were poorly correlated (R2 = 0.462); overall skin colour was more red at the base than in the middle of the petiole. Rhubarb character categories, in particular petiole number and petiole base thickness, need to be modified to better anticipate the range of expected values, and thereby contribute improved reproducibility and reliability to separate cultivars based on morphological characters.