In a study published in Annales Botanici Fennici, researchers from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences identified a new tree species in Yunnan Province, China. It belongs to the tropical genus Chisocheton of the Meliaceae family, and is distinguished by its extraordinarily long, cascading floral displays.

During field surveys in the Tongbiguan Provincial Nature Reserve in southwestern Yunnan, the trees stood out due to their immense inflorescences and large, softly hairy seed capsules. By comparing them with herbarium species and digitized records, researchers confirmed that they represent a new species and named it Chisocheton megathyrsus to refer to the extremely long inflorescences.

Chisocheton megathyrsus can grow up to 20 meters tall. Its most striking feature is the pendulous, many-branched inflorescence bearing clusters of small, fragrant, yellowish-white flowers. Besides its spectacular blooms, the species has large elliptical leaflets with a velvety texture and sizable, fuzzy, olive-brown fruits that can reach 10 cm in diameter.

Chisocheton megathyrsusis is morphologically similar to Chisocheton dysoxylifolius, known from Bangladesh to Thailand. However, it is distinct in multiple traits: a longer, hairier leaf stalk, leaflets with more secondary veins, longer inflorescence branches, hairless anthers, and its uniquely large, cup-shaped floral disc.

To date, Chisocheton megathyrsus is known only from Nabang Township in Yingjiang County, Yunnan, where it grows in humid tropical forests at altitudes of 200-400 meters within the protected Tongbiguan Nature Reserve. Its restricted known range in lowland tropical forest makes it vulnerable to threats like habitat fragmentation from deforestation and agricultural expansion.

Notably, for decades, herbarium samples of this tree have been misidentified as Chisocheton cumingianus subsp. balansae, previously the only recognized member of its genus in China. "The formal recognition of Chisocheton megathyrsus underscores the immense yet still-undocumented plant diversity in Yunnan's frontier forests,” said TAN Yunhong of XTBG.

Chisocheton megathyrsus (Image by TAN Yunhong)

Chisocheton megathyrsus (Image by TAN Yunhong)