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Agathis

Agathis

Agathis is a genus of tropical conifers which belongs to the Araucariaceae, the same family as the monkey-puzzles and Cook-pines (Araucaria) and the Wollemi Pine (Wollemia). Agathis trees are usually huge trees of lowland rain forests, though some grow in mossy forests on mountain tops, and another (as above) grows as low candelabra-like forms in low scrubland. The genus is distributed from Malaysia, Brunei and Indonesia, through New Guinea, Queensland and the eastern Solomons, to Vanuatu, New Caledonia, Fiji and New Zealand.

The genus is especially valuable for two reasons: firstly, its beautiful, high value timber, and secondly its valuable resin which is still used for many varnishes and lacquers. It is also a particularly challenging genus to understand taxonomically. Most herbarium specimens are sterile, the nomenclature is famously confused, there is very little morphological variation between the species and next to nothing is known about the phylogeny of the genus.

You can find out more about the systematics of Agathis by following the links to the left. If you need a specimen identified, you can either try and use my key (coming soon) or e-mail me with details of the pollen cone. Please note that sterile specimens cannot be confidently identified! A checklist of species currently recognized with correct names and typification details is available as the 'Taxonomy' page.

I'm presently working on the New Caledonian species of Agathis, with a view to applying molecular data to understand species limits in this group, where previous studies have relied entirely on the morphology of the few fertile collections. I've made hundreds of collections of DNA samples, and dozens of new herbarium collections for Oxford, Nouméa and Kew, in the course of two months of fieldwork in New Caledonia earlier this year. You can read more about the ideas that underpin this approach by clicking on the 'Species' link at the left hand side.

I hope this website is of use, or at least of interest, to you. If you have a query, a suggestion for its improvement, or anything obvious which is missing, please do get in touch with me - contact details as at the foot of this page. If you work on any aspect of the biology or use of Agathis I would love to hear from you.

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Obviously, never collect anywhere without (a) a permit from the appropriate authorities in the country in question, AND (b) permission from the person or people who own or control the land.

(1) Identifying Agathis

Agathis is an extraordinarily distinct genus. Two easy vegetative field characters alone suffice to differentiate members of the genus from all other living organisms. These are

(i) the completely flat leaves with parallel resin canals and (obviously) no venation.

(ii) the rounded, ball-like appearance of the growing tips.

Character (i) separates the genera Nageia (Podocarpaceae) and Agathis from all others. Character (ii) separates Agathis from Nageia (which like all other Podocarpaceae has pointy growing tips). If the plant has recently flushed with new growth, it may be difficult to tell the genera apart at first, so a further useful tip is to take a mature leaf and attenpt to fold it so that apex and base meet, and then smooth it with your fingers from the apex/base end to the fold. Coriaceous Agathis leaves will almost always snap. Nageia leaves, which tend to be a bit thinner and more supple, will only seldom snap.

The bark is also extraordinarily distinctive (see picture in Flora Malesiana I: 10 (3): 432), and with experience can usually be spotted from tens of metres away even in dense forest. From above, the trees are often emergent/predominant above the canopy and have a distinctive architecture and appearance. The pollen cones are also completely unmistakeable, but perhaps only to the trained eye, and they are quite difficult to describe.

(2) Collecting Agathis

From a taxonomic point of view, however, it is not the leaves which are important (although if they can be collected they should be) but the male cones. In the Araucariaceae, mature female cones shatter in the canopy, so the taxonomy of the genus is based almost entirely on characters of the pollen cone and the constituent microsporophylls. Shortly after anthesis, these are abscised and fall to the floor, where they often persist for many months in the thick and slow-rotting carpet of Agathis leaves. They are very much worth collecting. Have a look at the photos on the 'Images' page for an idea of what they look like. Spotting them in the leaflitter may be quite difficult at first, but a quick rummage at the very base of the tree usually recovers at least a few. They may well be partially rotted or disintegrated - obviously, if you can collect whole pollen cones they are much preferable, but if you can't see any that aren't damaged don't worry - partially damaged collections are still useful for microsporophyll characters.

I've tried spirit collection, and I've tried drying, and contrary to my fears dries pollen cones, although they do disintegrate, do not do so rapidly. I therefore think drying is preferable, and much more convenient as well. I recommend collection into thick paper bags (I use manila-paper brown envelopes from stationers for this purpose), folding the top over and sealing with a paperclip, and leaving them somewhere warm to dry the moisture from them before sending them home.