Post by Melanie on Jan 6, 2007 19:44:40 GMT 1
Pennantia baylisiana
New Zealand's rarest tree —
its discovery and propagation
Reproduced from an article by Professor G. T. S. Baylis
From The New Zealand Garden Journal (Journal of the Royal New Zealand
Institute of Horticulture), Vol. 2, No. 1, March 1997, pp. 12-13.
T. F. Cheeseman was an early Director of the Auckland Museum. He was
also the first botanical explorer of the Three Kings Islands. On his
visits in 1887 and 1889 he had only a few hours ashore, yet he found
six new plants. A more thorough search was clearly warranted but it
was not until 1945 that the Museum arranged for a scientific party to
camp on the main island. I was the botanist. By this time wild goats
had eaten the place out. Part was closely browsed grass but most was
kanuka forest or scrub. Cheeseman's novelties survived in small
numbers beyond browse range. It was easy to see that the grassland
offered nothing new, but the kanuka canopy was broken here and there
by other textures and shades of green. I located these places by
climbing trees at every vantage point and reached them deviously via
bluffs and screes since except in the main valley they were, even for
goats, a bit inaccessible.
In these clumps such things as puriri, mahoe and mangeao persisted
and I soon found the liane Tecomanthe speciosa and the rangiora with
a corky trunk like a cabbage tree - Brachyglottis arborescens. The
last little grove that I investigated lay near the highest point of
the island down a scree of boulders about 200m above the sea. I was
drawn to it by what looked like a karaka. I was soon gazing upon it
in disbelief since a third find seemed too much to expect. But this
was no karaka - its leaves were larger and recurved strongly in the
sun, its bunches of small green flowers sprang from the bare branches
below the leaves and there were no big berries - indeed none at all.
Dr W. R. B. Oliver, our last true biologist equally authoritative
about animals or plants was anxious to identify my finds and I sent
them to him. Lacking time and experience, I feared I might blunder by
getting a family wrong. This danger proved real indeed, for Oliver
himself put the pseudo-karaka in the Anacardiaceae, which is close to
the karaka family, whereas had I been able to send fruits he would
have realized that the resemblance to karaka is misleading, the
proper family being Icacinaceae to which Pennantia belongs.
It was a European botanist working with herbarium sheets who realised
that the Three Kings specimens were Pennantia: indeed concluded that
the tree was just a stray P. endlicheri from Norfolk Island. But
herbarium sheets don't tell all - thicker leaves recurving curiously
in the sun, stouter stems and flowers on leafless branches rather
than at the ends of twigs so distinguish the Three Kings tree, that
the two have little resemblance. So when our Flora is next revised
either the definition of Pennantia will be broadened to accommodate
cauliflory (flowers arising on old wood) or Oliver's genus
Plectomirtha will reappear as a member of the Icacinaceae. The former
seems the wiser course as P. baylisiana does occasionally flower at a
branch tip. Moreover, the objective of taxonomy is to synthesise and
there is no synthesis when a species has a genus to itself.
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).
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 "Plectomirtha" beyond doubt.
Cultivation of Pennantia baylisiana
It is now 50 years since the tree was discovered and it is still not
common in cultivation. This is because the species is dioecious, the
sole remaining tree being female. Whilst some self-pollination does
occur, nearly all the fruit produced are sterile. In cultivation the
species readily cross-pollinates with the kaikomako, Pennantia
corymbosa, producing hybrids with intermediate features. One
selection from this cross has been named Pennantia 'Otari Debut'.
Propagation is from hardwood cuttings taken in autumn. Rooting can
take up to 10 months and young plants will often collapse and die in
the first twelve months.
Plants are easy to grow provided they are given protection from
frost, and can tolerate shade, growing well under the canopy of
larger trees. Trees tend to produce multiple stems and can grow to
more than 5 metres high. The main ornamental value of the tree is its
large glossy foliage, looking as Professor Baylis said, like large
karaka leaves.
Mature trees in cultivation can be seen at the Otari Native Botanic
Garden, the Auckland University Grounds, and at HortResearch, Mount
Albert, Auckland.
Notes on cultivation by Mike Oates
www.rnzih.org.nz/pages/pennantia.htm
New Zealand's rarest tree —
its discovery and propagation
Reproduced from an article by Professor G. T. S. Baylis
From The New Zealand Garden Journal (Journal of the Royal New Zealand
Institute of Horticulture), Vol. 2, No. 1, March 1997, pp. 12-13.
T. F. Cheeseman was an early Director of the Auckland Museum. He was
also the first botanical explorer of the Three Kings Islands. On his
visits in 1887 and 1889 he had only a few hours ashore, yet he found
six new plants. A more thorough search was clearly warranted but it
was not until 1945 that the Museum arranged for a scientific party to
camp on the main island. I was the botanist. By this time wild goats
had eaten the place out. Part was closely browsed grass but most was
kanuka forest or scrub. Cheeseman's novelties survived in small
numbers beyond browse range. It was easy to see that the grassland
offered nothing new, but the kanuka canopy was broken here and there
by other textures and shades of green. I located these places by
climbing trees at every vantage point and reached them deviously via
bluffs and screes since except in the main valley they were, even for
goats, a bit inaccessible.
In these clumps such things as puriri, mahoe and mangeao persisted
and I soon found the liane Tecomanthe speciosa and the rangiora with
a corky trunk like a cabbage tree - Brachyglottis arborescens. The
last little grove that I investigated lay near the highest point of
the island down a scree of boulders about 200m above the sea. I was
drawn to it by what looked like a karaka. I was soon gazing upon it
in disbelief since a third find seemed too much to expect. But this
was no karaka - its leaves were larger and recurved strongly in the
sun, its bunches of small green flowers sprang from the bare branches
below the leaves and there were no big berries - indeed none at all.
Dr W. R. B. Oliver, our last true biologist equally authoritative
about animals or plants was anxious to identify my finds and I sent
them to him. Lacking time and experience, I feared I might blunder by
getting a family wrong. This danger proved real indeed, for Oliver
himself put the pseudo-karaka in the Anacardiaceae, which is close to
the karaka family, whereas had I been able to send fruits he would
have realized that the resemblance to karaka is misleading, the
proper family being Icacinaceae to which Pennantia belongs.
It was a European botanist working with herbarium sheets who realised
that the Three Kings specimens were Pennantia: indeed concluded that
the tree was just a stray P. endlicheri from Norfolk Island. But
herbarium sheets don't tell all - thicker leaves recurving curiously
in the sun, stouter stems and flowers on leafless branches rather
than at the ends of twigs so distinguish the Three Kings tree, that
the two have little resemblance. So when our Flora is next revised
either the definition of Pennantia will be broadened to accommodate
cauliflory (flowers arising on old wood) or Oliver's genus
Plectomirtha will reappear as a member of the Icacinaceae. The former
seems the wiser course as P. baylisiana does occasionally flower at a
branch tip. Moreover, the objective of taxonomy is to synthesise and
there is no synthesis when a species has a genus to itself.
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).
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 "Plectomirtha" beyond doubt.
Cultivation of Pennantia baylisiana
It is now 50 years since the tree was discovered and it is still not
common in cultivation. This is because the species is dioecious, the
sole remaining tree being female. Whilst some self-pollination does
occur, nearly all the fruit produced are sterile. In cultivation the
species readily cross-pollinates with the kaikomako, Pennantia
corymbosa, producing hybrids with intermediate features. One
selection from this cross has been named Pennantia 'Otari Debut'.
Propagation is from hardwood cuttings taken in autumn. Rooting can
take up to 10 months and young plants will often collapse and die in
the first twelve months.
Plants are easy to grow provided they are given protection from
frost, and can tolerate shade, growing well under the canopy of
larger trees. Trees tend to produce multiple stems and can grow to
more than 5 metres high. The main ornamental value of the tree is its
large glossy foliage, looking as Professor Baylis said, like large
karaka leaves.
Mature trees in cultivation can be seen at the Otari Native Botanic
Garden, the Auckland University Grounds, and at HortResearch, Mount
Albert, Auckland.
Notes on cultivation by Mike Oates
www.rnzih.org.nz/pages/pennantia.htm
