Our native plants: Pennantia baylisiana

Pennantia baylisiana once held the dubious title of being the rarest plant in the world with only one female tree in its native Three Kings Islands. This dire state of affairs began to be remedied in 1945 when Professor Geoff Baylis (1913-2003) of Otago University took six cuttings from the (then) goat-ravaged islands to be grown on at the Government research station at Mt Albert. Three survived and more cuttings were taken from them and then, glory be, one plant spontaneously produced female and male flowers! It is thought that the one surviving tree, while “fundamentally female”, also has some “low-level” male characteristics.

Pennantia baylisiana, complete with berries, photographed in Wellington Botanic Gardens last weekend. Apparently the berries ripen to blue. There is also a specimen growing in the Auckland Regional Botanic Gardens. Photo: Sandra Simpson

The Terrain website says: “The single tree known in the wild grows on a scree slope on the northern face of Great Island in the Three Kings group off Cape Reinga, New Zealand. It is still alive today some 65 years later, and has not produced any seedlings on the islands. Forty years after the Pennantia was found Ross Beever (1946-2010), a scientist with Landcare Research, tried to see if he could induce it to produce seed. He was successful and the resulting seedlings have proved to be more fertile than their mother.”

Oratia Native Plant Nursery which assisted Ross in his project, donates all proceeds from the sale of Pennantias to help fund botanical research and to minimise the risk of extinction of other species.

It should be noted that Professor Baylis took some drastic action to try and save the tree (Journal of the Royal New Zealand Institute of Horticulture, Vol. 2, No. 1, March 1997, pp. 12–13). Read the entire article here.

“Propagating this lone and sterile tree, not in the best of health because of insect damage, seemed urgent. There was a detachable shoot at its base, which took root in a damp sheltered place in my Dunedin garden and is now very like its parent with four slender trunks. But its canopy trimmed by occasional frost rather than repeated salty gales is taller (7m),” Prof. Baylis wrote.

“While I was unsure that this shoot had really rooted, I was worried by failure both at the Plant Diseases Division at Mt Albert and at Duncan and Davies, New Plymouth, to strike cuttings from the crown. I asked George Smith, the chief propagator at New Plymouth, what I might do to provide better cuttings. ‘Cut the tree down,’ he said, and while I shuddered at the thought, he explained that he was confident about rooting shoots from the stump. But would there be any? Well, the tree had four trunks so I dared to sever one. A year later, the shoots were there. The naval launch on which I was a guest gave them a quick passage to New Plymouth, which happened to be its next port, and Mr Smith soon placed the survival of [the tree] beyond doubt.”

Brave man!

In 2010 New Zealand scientists took 1600 seeds back to the islands to plant. Read more here. The tree’s status today is described as ‘nationally critical’.

Lawrie Metcalfe in The Cultivation of NZ Trees and Shrubs (Raupo, 2011) says in the garden P. baylisiana will grow to 3-4m. “Where a large-leafed tree is required for effect, this magnificent foliage plant is ideal.”

A cross of P. baylisiana with P. carymbosa seen growing at Otari Wilton’s Bush in Wellington. The hybrid has been named Otari Debut. Photo: Sandra Simpson

P. corymbosa (kaikomako) is a relatively common forest tree of mainland New Zealand. Apparently it hybridises quite easily with P. baylisiana. P. cunninghamii (brown beech) is a rainforest tree of eastern Australia. The final tree in the family is P. endlicheri, native to Norfolk Island, once thought to be identical to P. baylisiana but now proved not to be.

The same day Prof. Baylis found P. baylisiana, he also came across the woody vine, Tecomanthe speciosa and managed to save that from extinction too, but that’s another story.

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2 thoughts on “Our native plants: Pennantia baylisiana

  1. I was fascinated to look further at this genus and see the other Pennantia in Australia and Norfolk Island. Such an interesting genus and thanks for a great story about how this species was saved from the precipice edge of extinction.

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