Women plucking tea on Hainan Island, China. Photo credit: Marco Bertona
Researchers have identified a new species of wild-grown tea trees in the tropical forest on China’s Hainan Island. Leaves plucked from ancient 30-foot plants and prized by local tea makers, which were informally known as Hainan dayezhong (large leaf), are now formally christened C. sinensis var. hainanica, a newly discovered species in the Camellia genus.
The findings, published in the journal Agrobiodiversity, analyzed 500 samples to discover the distinct taxonomic position of native Hainan tea. The species grows among many cultivated varieties transplanted over centuries. A side benefit of the research is a catalog of the genetic diversity of several camellias, including C. sinensis var. assamica, the floral C. chrysanth (golden camellia), C. euphorbia, C. crassicolumna, and fragrant C. osmanthanot that are not used in tea making.
Morphologically, C. hainanica is notable for its substantial size of leaves (even larger than assamica leaves, which are 4 to 8 inches long and 1.5 to 2.8 inches wide). While transplanted cultivars typically remain shrubs, this variety can grow into a tree form, with cultivated specimens reaching 3 to 4 meters and wild ones up to 10 meters. The leaves are large, rounded, or oval and contain higher levels (35%) of polyphenols and caffeine (6%) than other tea varieties, making them particularly suitable for black tea production. Although the plants resemble assamica, they are more closely related to the small leaf sinensis branch. This is likely because Hainan was once part of mainland China. Researchers note the initial separation occurred in the Paleocene epoch, while the major part of the rotational drift from the mainland occurred in the Eocene epoch.
According to HICN, the Hainan large leaf variety has a rich cultural significance. Records from the Ming Dynasty, dating back 500 years, indicate that wild tea from Hainan was considered worthy of tribute to the imperial court. This historical importance adds a layer of connection and appreciation for the Hainan large-leaf variety. In modern times, the cultivation area of this tea variety has expanded significantly, with its products exported to more than 30 countries and regions.
In the academic paper, researchers cited geographic isolation as one of the leading causes of species formation. “When populations of the same breeding stock separate, they face independent evolutionary histories defined by natural selection, genetic drift, adaptation, and colonization to local conditions. As a tropical island, Hainan has extensive rainforests that provide high-quality growing environments for plants, and the island’s geography provides the necessary geographic isolation for new species to arise,” according to researchers.
Researchers noted that “by constructing a phylogenetic tree between Hainan tea and globally cultivated tea trees, it can be observed that Hainan tea does not belong to either CSS (C. sinensis var sinensis) or CSA (C. sinensis var assamica), but rather forms an independent branch and clusters into a single taxon.”
Researchers concluded that confirming the Hainan Large-Leaf Camellia as a distinct species provides valuable resource conservation and molecular breeding insights. It underscores the unique biodiversity of Hainan Island, a natural resource of immense value and beauty, and highlights the importance of preserving and studying this unique tea variety.