A research team led by Kyoto University and Osaka Metropolitan University botanists has described a new species in the genus Lilium from Japan.

Lilium is a large genus of herbaceous flowering plants in the family Liliaceae.

Most Lilium species are native to the northern hemisphere and their range is temperate climates and extends into the subtropics.

In a new study, Dr. Seita Watanabe from Kyoto University and Osaka Metropolitan University and colleagues aimed to clarify the evolutionary history of the Lilium maculatum–Lilium pensylvanicum complex.

“We questioned the classification used up to now for the complex, which usually has orange flowers,” they said.

“These lilies have high ornamental value, having been exported from Japan for more than two centuries.”

“There have been only four taxonomic groups, but we sought evidence to prove that there were more.”

For the study, the researchers collected and analyzed various Lilium specimens, including their genetic material and images, from across Japan.

“The results of our extensive work revise the conventional classification into eight taxons, including what we have named Lilium pacificum, the first new species of Japanese lily in 110 years,” they explained.

According to the team, Lilium pacificum can be found in the coastal areas of Honshu from Ibaraki Prefecture south to Shizuoka Prefecture and the Izu Islands.

“It has an interesting characteristic: the tips of its leaves are curved into a claw-like shape,” Dr. Watanabe said.

“Based on the new understanding of these eight taxonomic groups, we found that seven are endemic to Japan, each adapted to its environment, whether coastal or mountainous, and evolving unique traits.”

“Our research shows that these plants have differentiated through complex processes, and we hope that our work will provide clues for speciation studies.”

“In the past, individual differences may have been overlooked because of the apparent simplicity of the plants.”

“Through this research, I was reminded of the importance of morphological observation.”

The discovery of Lilium pacificum is reported in a paper published in the April 2024 issue of the journal Taxon.

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Seita T. Watanabe et al. 2024. Biosystematic studies on Lilium (Liliaceae) II. Evolutionary history and taxon recognition in the L. maculatum–L. pensylvanicum complex in Japan. Taxon 73 (2): 447-474; doi: 10.1002/tax.13141