Ocean Expo Park Announces World-First Exhibition of New Species 'Thalictrum yambaruense' Following Successful Seed Propagation

The Tropical Dream Center (Churashima Plant Garden) is pleased to announce the first-ever public exhibition of 'Thalictrum yambaruense,' a new plant species endemic to the northern part of Okinawa Island (the Yanbaru region).

The Okinawa Churashima Foundation has been conducting intensive cultivation research for conservation purposes. Through a process of trial and error regarding temperature, humidity, lighting, and seed storage methods, the Foundation has successfully achieved the world's first propagation of this species from seeds. This discovery was formally published as a new species in the international plant taxonomy journal 'Phytotaxa' (Vol. 696, No. 1) on March 28, 2025. Currently, the Foundation is the only organization in the world possessing seedlings sampled for research and conservation; the seeds used for propagation were harvested from these cultivated plants.

These rare propagated individuals will be displayed for a limited time in the exhibition greenhouses and the Yanbaru Gallery.

**Species Profile: Thalictrum yambaruense** * **Family:** Ranunculaceae * **Scientific Name:** *Thalictrum yambaruense*

Thalictrum yambaruense is an extremely rare endemic species found only on steep rocky cliffs near waterfalls in the Yanbaru region, a UNESCO World Natural Heritage site. In 2025, a research group including the Okinawa Churashima Foundation and Tohoku University Graduate School of Life Sciences described it as a new species, naming it after its place of origin.

According to the Okinawa Prefecture Red Data Book, it is classified as Critically Endangered (IA). There is only one confirmed habitat in the wild, and the population count is extremely low.

**Key Characteristics:** - **Size:** 4–10 cm in height. - **Breeding History:** First fruiting confirmed in March 2024. Germination occurs 2 months after sowing, with flowering at 6 months. - **Flowering Season:** February to October (Peak: May–June).

**Exhibition Details:** - **Best Viewing Period:** Until mid-June 2026. - **Location:** Tropical Dream Center (Phalaenopsis Greenhouse and Yanbaru Gallery), Ocean Expo Park.

**About Ocean Expo Park and the Tropical Dream Center:** Ocean Expo Park is a national park located on the site of the 1975 International Ocean Exposition. The Tropical Dream Center, one of its premier facilities, offers a unique botanical experience within architecture reminiscent of ancient ruins, showcasing over 2,000 orchids and various tropical plants.