New Lasianthus genue found in Ru Linh Primary Forest in central Vietnam

A new species belonging to Lasianthus genus has been found in Ru Linh Primary Forest in Vinh Linh District, the central province of Quang Tri, Vietnam.

The new species was found after a long time of collecting specimens in the central provinces of Quang Tri and Quang Binh and described by botanists from the Mientrung Institute for Scientific Research (MISR)’s Institute for Life Sciences; officials from Cam Lo – Dong Ha Forest Ranger; and representatives from Kagoshima University Museum, Japan.

New species of Lasianthus discovered in Ru Linh Primary Forest. Photo: Le Anh Tuan

Lasianthus is a large genus in the Rubiaceae family, comprising 292 species distributed worldwide. In Vietnam, 74 species of this genus have been recorded. The species Lasianthus trongii V.S. Dang, T.A. Le & Tagane is named in honor of Nguyen Dinh Trong, who has dedicated over 40 years to protecting the Ru Linh Primary Forest, where this species was first discovered and collected.

In 1977, Trong, along with several residents, took on the responsibility of safeguarding the Ru Linh Primary Forest. Thanks to his unwavering commitment, this nearly 100-hectare primary forest, the last of its kind in the Quang Tri lowlands, has remained intact to this day.

Lasianthus trongii is a shrub that reaches a height of one to three meters, featuring smooth, hairless stems. Its leaves grow in opposite pairs, with elliptical to lanceolate blades that are hairless on both sides, pointed tips, nearly rounded bases, entire margins, and 6–8 pairs of secondary veins. The petioles, measuring 2–3 mm in length, are also hairless, while the stipules are small and triangular.

The plant produces inflorescences in the form of cymes, each bearing seven nearly sessile white flowers. The calyx is bell-shaped to truncated-conical, hairless, and divided into four triangular lobes. It has four stamens attached to the corolla tube, a four-locular ovary, and a style measuring 1.5–2 mm in length, covered in fine hairs, with three lobes. The fruit is a smooth, ovoid to spherical drupe that ripens to a striking orange-red, making it easily recognizable in the wild.

Lasianthus trongii closely resembles L. tamdaoensis and L. kailarsenii but is clearly distinguishable by its leaf, flower, and fruit morphology. Its most distinctive feature is its vibrant orange-red fruit, which contrasts sharply with the blue fruit of the other two species. Found in two areas across Quang Binh and Quang Tri provinces, this species has a small population. Due to its restricted distribution and limited numbers, it has been proposed for Endangered (EN) status under the IUCN 2024 assessment.

Quang Hai – Linh Pham