The genus Thismia consists of small herbaceous plants that are entirely mycoheterotrophic, drawing their nutrients from fungi. These plants have garnered significant attention from researchers due to their peculiar appearance and remarkably intricate and diverse flower morphologies. There are currently 105 known species and one variant worldwide, primarily distributed in tropical and subtropical regions of Asia, temperate regions of Australia, and tropical regions of the Americas.
During a field survey in the Malipo Laojunshan Provincial Nature Reserve in southwestern China in 2019, researchers from the Southwest China Germplasm Bank of Wild Species stumbled upon a plant with a particularly unique and striking structure, resembling something out of a science fiction movie—an "alien." Collaborating with the Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences, researchers meticulously studied its morphological structure, reviewed relevant literature, and gathered molecular evidence. As a result, they identified this species as a previously undescribed member of the genus Thismia. Named after its type locality, the species is now officially known as Thismia malipoensis J. D. Ya & W. B. Yu. The findings of this study were recently published in Weidneria.
Image of Thismia malipoensis plant and habitat provided by the research team.
The genus Thismia comprises small herbaceous plants that are entirely mycoheterotrophic, drawing attention from researchers due to their peculiar appearance and extraordinarily complex and diverse floral morphology. There are 105 known species worldwide, along with one variety, primarily distributed in the tropical and subtropical regions of Asia, temperate regions of Australia, and tropical regions of the Americas.
In a recently published paper, researchers conducted a study focusing on the "extraterrestrial" aspects of these plants. By integrating molecular fragment data, they constructed a phylogenetic tree of the new species and its closely related species, determining its systematic position.
A close-up of Thismia malipoensis, provided by the research team.
Biogeographical analysis indicates that the ancestral distribution of the genus Thismia spans from southwestern China to the India-Myanmar region and the Sunda Shelf. Subsequently, it dispersed eastward to southeastern China and Japan, and southward to New Guinea and Australia.
Furthermore, Thismia species in China have originated from at least two distinct ancestors. Geographic isolation led to the divergence between Thismia malipoensis and its closely related species T. abei from Japan approximately 17.47 million years ago.
Thismia malipoensis was only found in about 10 individuals at its type locality, and no new individuals have been discovered in subsequent surveys. The species is assessed as "Critically Endangered (CR)".
Researchers note that like this new species, most Thismia species have only been found or collected once or a few times, with very small populations. As the seed germination and growth of Thismia species highly depend on specific symbiotic fungi, the most effective way to conserve them is through habitat protection to achieve in-situ conservation.
It is understood that southeastern Yunnan is one of the important hubs connecting China and the tropical Southeast Asian plant floristic regions. It preserves typical ancient tropical karst landscapes, is one of China's biodiversity hotspots, and is also a typical ecologically fragile area. With the support of the National Important Wild Plant Germplasm Resources Bank and relevant projects in Yunnan Province, the Southwest China Wild Plant Germplasm Resources Bank will continue to strengthen the investigation and collection of plant germplasm resources in this region to ensure the security and long-term preservation of China's strategic biological resources.
Related paper information: https://doi.org/10.3372/wi.54.54102
