Student Scholars & Faculty Mentors

Economic Botany Research: Colocasia-Xanthosoma species identification in market tubers.

Name: Lynn, Duncan
Advisor: Christopher Hardy
Department: BIOL
Award: Neimeyer Hodgson
Abstract: The value of knowing exactly what one is eating cannot be overstated. However, some vegetable produce sold in area markets are distributed to the consumer under various vernacularnames(i.e., common names)which are taxonomically ambiguous and cannotbe matched precisely totheirspecies identity.Vegetables of the Colocasia-Xanthosomacomplex, for example, are cormosestem tubers produced by as many as three different tropical plant species (C. esculenta, C. antiquorum, and X. sagittifolium) and which are a subsistence food crop throughout the tropics (Heywood et al. 2007). These tuber vegetables can be found in Lancaster County markets under a variety of names including taro, American taro, dasheen, malanga coco, malanga blanca, malanga lila,yautía (red or white), or eddoe.Based on my preliminary survey at area markets, very similarlooking tubers often are sold under very different common names (e.g.,eddoe, malanga, and yautia eddoe in Figure 1).Precise identification of thesespecies names provides a link between cultural naming systems and scientific research (Bye, 1986). Are these tubers all the same (i.e. from the same species or cultivar), as their morphology would suggest, or are they from different species or cultivars? Other times, one finds the same common name applied to tubers of verydifferent sizes and shapes(e.g., “malanga” in Figure2), and it is not clear that these common names are being applied correctly or consistently to the same species in American produce markets. Despite them having the same common name “malanga,” the tubers are so different that one might think that they came from different species in this complex.Unfortunately, the literature on how to tell species in the complex apart is based on features of leaves and flowers–not the tubers(Mayoet al. 1997). Yet tubers are the only parts available in the produce isle, leaving the curious consumer wondering what they are eating. The goal of this research is to take a two-way approach to identifying tubers of the Colocasia-Xanthosomacomplex sold in markets across Lancaster, Pennsylvania. Xanthosomasagittifolium, Colocasia esculenta, and Colocasia antiquorumare all members of the philodendron family, Araceae,andare grown not only for their edible tubers, but also for their edible leaf petioles and ornamental value(Heywood et al. 2007). The species of Colocasiaare native to Southeast Asia and the Pacific Islands(Ahmed, et al. 2020)and Xanthosoma sagittifoliumis native to Central and South America(Serviss, et al. 2000). Despite their being native to separate regions, all species are now cultivated for their edible tubers in both the Pacific and Americas, and their tubers find their way to Lancaster County produce isles.