Twenty-three unique new plant species have been found over the past five years in the mysterious Shennongjia Nature Reserve in central China's Hubei Province, a researcher said Wednesday.

"We are pretty much sure that the new species, which have not been discovered elsewhere in the world, are new members of the plant kingdom," said Yang Jingyuan, head of the reserve's research institute.

The English or Latin names of the new plant species were not available yet, Yang said.

Before the latest discoveries, the 705-square-kilometer reserve was already home to more than 100 plant species not found anywhere else on earth, according to the center.

With abundant rain and water resources and a mid-latitude location, Shennongjia is home to more than 3,700 species of plants and at least 1,060 kinds of animals. At least 39 plant species and 70 animal species,including golden monkeys, are under state protection.

The new discoveries showed the "gene pool" of plants and animals was still expanding, said Yang.

Researchers had identified 143 previously undocumented plant species in Shennongjia since 2006, excluding the 23 new varieties that are unique to the area, he added.

Scientists had also discovered 16 kinds of snakes and 270 kinds of insects that were new to Hubei Province.

Lying between the transitional zone of south-west mountains and low hills of central China, the reserve is in the transitional zone between the sub-tropical and temperate climates.

About 96 percent of the reserve is covered by primeval forest, including hundreds of square kilometers that is not explored by humans.

The region is criss-crossed with mountains and rivers and has 31 peaks with altitudes more than 2,500 meters above the sea level.

Sea swallows have been found living in the Shennongjia mountains which, according to scientists, were covered by oceans before they rose above the sea during the Devonian period about 405 million to 345 million years ago.

The number of albino animals, including bears, snakes and magpies, found in the reserve have also baffled scientists.

The unique and complicated geographic environment provided shelter for animals and plants from glacier activities during the Quaternary Period 2.5 million years ago. It has preserved an array of plants that existed in the Tertiary Period and is widely called a home of living plant fossils.

The area is also believed to be home to the legendary Bigfoot-like ape man.

The Hubei Wild Man Research Association said earlier this month that it was considering launching a high-profile search for the elusive creature, almost 30 years after the last organized expedition to seek the legendary beast in the early 1980s.

It said it would recruit the expedition members from around the world.

The United Nations Educational, Scientific and Cultural Organization (UNESCO) put Shennongjia on its World Network of Biosphere Reserves list in 1990.