Curious plants: Cook’s pine

Although the tree as a whole is interesting, the first thing I want to mention about Araucaria columnaris is its cones.

The male cones on a Cook’s pine. Photo: Sandra Simpson

I spotted the bronze-coloured cones on a young tree in a Western Bay of Plenty garden last week and was introduced by the owner to some of that “isn’t Nature grand” information. The Cook’s pine carries only male cones (elongated) on its lower branches and only female cones (round) on its top branches – he bounced a couple of the lower branches and the fine, sulphur-coloured pollen come away in a cloud. Thanks to the placement of the cones, Nature ensures that this pollen doesn’t pollinate the tree it’s come from but is carried by the wind to the tree next door.

I have seen online references to Cook pines (named for the great English navigator James Cook) coming from the Cook Islands (also named for James). But this is incorrect. Araucaria columnaris are native to New Caledonia and gave Isle des Pins its name – incidentally, there they grow on coral substrate and are sometimes known as coral pine. They have also naturalised on the Hawaiian islands.

Cook pines grow very tall – some 60m –  but cultivated trees usually don’t grow very straight. The one I saw was at an almost 45-degree angle from the ground, despite the owner doing his best to pull it back to true.

The round female cones at the top of the tree. Photo: Sandra Simpson

The owner, who is very knowledgeable about this family of trees, says some people  believe Araucaria columnaris have a season for cones, pollen and seeds – but his experience is that the trees have cones, and so seeds, at any time of the year and are not necessarily in synch with one another.

They were some of the first trees on the planet and, as such, have some simple habits – such as not flowering. They are also one of the few conifers native to the southern hemisphere.

When Cook pines are young they can easily be mistaken for Norfolk Island pines (Araucaria heterophylla).

Read much more about the Araucaria and their close relatives the Agathis (kauri) families here and here (lots of photos with this one).

Cook’s pines growing in New Caledonia. Photo: my LifeShow, via wikimedia commons

Tuesday digest

I’ve been watching a DVD called How to Grow a Planet, a British TV series from 2012 presented by Professor Iain Stewart, a Scottish geologist – and some of the information is absolutely fascinating. He was in New Caledonia for one bit of it, showing us Cook’s pines (Araucaria columnaris) and then moved inland to find what he called “the world’s first flower”.

Yep, plants haven’t always flowered – conifer pollen and fern spores being two of the very ancient ways of plant reproduction. The oldest living flowering plant on our planet, reaching back at least 130 million years, is Amborellaceae, a family that includes just one known species, Amborella trichopoda (see a photo here). Often described as a “living fossil,” this small woody plant grows only on New Caledonia.

See a clip of the Prof climbing the world’s tallest tree (other clips available on the right-hand menu).

“The Big Bloom – How Flowering Plants Changed the World” is a National Geographic article that may be read here. The land on this planet was, before the advent of flowers, almost entirely green and much of it comprised ferns, cycads and conifers.

I’d been thinking I hadn’t see or heard much about the show gardens at the recent Sydney Garden Show – Catherine Stewart (no relation to the Prof) was getting the same reaction from people who knew she’d been so has posted a review on her Garden Drum website.

Have you heard of Egyptian walking onions? Neither had I until recently. The name made me curious enough to find out a bit more – here is an informative American site and here’s a place to buy the bulbs in New Zealand (they’re also available on Trade Me).

Allium proliferum have a shallot-like onion at the base and produce bulblets at the top of the stem (usually, they don’t flower) which, if heavy enough will drag the foliage down and take root in the ground, hence the name “walking” onion.