Pohutukawa, New Zealand's Christmas tree may have originated in Australia

Pohutukawa in bloom. Photo / Michael Cunningham

New Zealand's iconic Christmas Tree, the pohutukawa, may have originated from Australia, a new study says.

A fossil research report from the University of Adelaide published in the American Journal of Botany described the discovery of two new fossil species of pohutukawa and related species.

Found near St Helens, on the East Coast of Tasmania, the fossils are said to be about 25 million years old.

Researcher Myall Tarran said the fossils showed the diversity of trees that once grew in Australia, and that related species of pohutukawa were part of the great supercontinent Gondawana, which included Papua New Guinea, the Philippines, New Caledonia and New Zealand.

"These species may not have been as well adapted for long-distance dispersal as those other species, and so it is likely that they originated (in Australia)," Tarran said.

Tarran said the pohutukawa, also known as the New Zealand Christmas Tree, was one of New Zealand's most iconic flowering plants.

It held a special place in the hearts of Kiwis, he said, and was of particular significance in Maori culture.

The pohutukawa's bright red blossoms, which looks a bit like fireworks, are usually at full bloom in early summer - around Christmas time.

It belongs to the myrtle tree family, which is found all over the South Pacific.

"It is also one of, if not the, most widely spread flowering plant groups in the Pacific," said Tarran.

"It grows in Hawaii, Papua New Guinea, New Caledonia, Tahiti, the Bonin Islands near Japan, on sub-Antarctic Islands and many other islands in between, as well as...in Africa and South America."

But although the species is believed to have originated in Australia, it is not found there today.

"Previous work we have done described the oldest fossils of Metrosideros (scientific name for the species) from...35-40 million years ago in Tasmania, showing that the genus once did occur in Australia but has since become extinct," Tarran added.

"The question still remains as to why they became extinct in Australia."