Staghorn Ferns in Botanical Gardens: Which Species Do We Really Cultivate or Trade?

ABSTRACT Horticultural collections of ornamental plants are vital elements in our efforts to conserve threatened plants, such as species of the staghorn fern genus Platycerium . Accurate species identification in these collections is often challenging but crucial to ensure the objectives of ex situ conservation. Here, we promote the establishment of reference DNA barcode libraries as an effective approach to take on the challenge to detect mislabeled accessions. To achieve this goal, a reference dataset was assembled employing a total of 287 accessions that were mainly obtained from the staghorn fern collections cultivated at the Xishuangbanna Tropical Botanical Garden, Yunnan, China. Five chloroplast genome loci were assessed as DNA barcodes reflecting their wide utilization in plant systematics. The results confirmed not only the utility of commonly used chloroplast DNA fragments as DNA barcodes for these ferns but most importantly found no obvious evidence for frequent misidentification of staghorn fern accessions maintained in botanical gardens, although some mislabeling was detected. The established reference dataset enabled us to secure the species identity of staghorn fern accessions handled in conservation practices or commercial trade. In turn, the application of DNA barcoding was confirmed as an effective tool to secure the species identity of accessions used in ex situ conservation collections of staghorn ferns by enabling reliable identification of all individuals, especially immature individuals that lack the morphological characteristics of adult plants utilized in expert identification keys. In conclusion, assembled DNA barcoding reference datasets are promoted as a practical approach to be applied in horticultural collection management but also for regulating the plant trade.