SINGAPORE - Two species of plants new to science have recently been discovered by researchers at the Singapore Botanic Gardens, Minister for National Development Khaw Boon Wan said in a blog post on Thursday (June 4).

The two plant species - Hanguana rubinea and Hanguana triangulata - are not only new to science, but can also be found only in Singapore, said Mr Khaw.

"This makes the discovery especially significant," he added. "Incidentally, the two new Hanguana plant species have red and white berries, our national colours."

He added that these were "nature's timely gift" to Singapore, given that this year is the Republic's 50th birthday.

Before the discovery, botanists had assumed that there was only a single species of the plant, Hanguana malayana, in Singapore.

But researchers examining a group of forest herbs belonging to the genus Hanguana, found "remarkable differences in the plants", such as their size, flower structure, colour of the ripe fruits, and the shapes of their seeds.

"As these plants are sometimes situated close to walking paths, visitors to Bukit Timah or MacRitchie would have passed these plants many times without realising that some of these are in fact new species," Mr Khaw said.

The two new species come on the heels of the discovery in 2014 of the Zingiber singapurense, a ginger. Singapore now has three plant species which are found nowhere else in the world.

In the blog post, Mr Khaw also said that 30 plant species thought to be extinct in the Republic have also been re-discovered. Forest surveys also found six species of plants new to Singapore.

"These discoveries testify to the importance of biodiversity research. It allows us to better understand our local flora and fauna," said Mr Khaw.