Hide and Seek: Molecular Barcoding Clarifies the Distribution of Two Cryptic Duckweed Species Across Alberta

Regional and global biodiversity may be underestimated due to the presence of cryptic species: species that are morphologically similar, but genetically distinct. Here, we focus on two cryptic duckweed species, Lemna minor L. and Lemna turionifera Landolt, which have overlapping geographic ranges and are easily mistaken for one another. We developed species-specific primers based on DNA barcoding sequences to facilitate the rapid identification of these two monomorphic duckweeds, allowing us to investigate their presence and distribution in Alberta, Canada. While current reports indicate the presence of L. turionifera (and the morphologically distinct Lemna trisulca L.) in Alberta, our data indicate that L. minor is also present, predominantly in the southern part of the province. Thus, this paper (i) contributes to the accuracy and completeness of a regional flora, and ( ii) provides useful and flexible tools for the rapid molecular identification of cryptic Lemna species, which are of wide interest in diverse fields such as biotechnology, toxicology, bioremediation, and ecology.