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AGATHIS - A conifer that doesn't look like one.
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Posted by sequoia_stiffy mf'n oakland, ca (My Page) on Sun, Dec 16, 07 at 3:00
| Saw a large agathis for the first time today. Didn't realize what an odd thing this is - a conifer that doesn't look like one. Seems like this sort of thing could be the missing link between flowering plants and gymnosperms, or just another weird-ass thing to come out of australia. Very fascinating, though. Anybody have any ideas or experience about growing one, germinating them, caring for them, etc?
Also, does anybody have any idea about what the so-called "missing link" might be between gymnosperms and angiosperms, when this enormous branch-off of evolutionary difference occurred and what species were involved (i.e. - what were the "first" angiosperms)?
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Follow-Up Postings:
RE: AGATHIS - A conifer that doesn't look like one.
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| You didn't take any pictures of that Agathis did you? Post them if you did! (please) Recent DNA analysis has shown that Amborella trichopoda is the oldest living Angiosperm, with fossils of this (or a closely related plant) going back 130 millions years. But it's still not the "missing link" between Angiosperms and Gymnosperms. Also, no living conifer has been shown to be basal in relation to the Angiosperms, ie. they aren't closely related to the "missing link". No other plant of any kind has been shown to be related to both Gymnosperms and Angiosperms either(ie. a descendant of the "missing link"). As far as I know the current most widespread theory about when the "enormous branch-off" occurred was about 150 millions years ago, but some lesser accepted theories say it occurred as long ago as 400 million years ago. I'm not exactly sure which conifer is considered the oldest, but I'm sure someone on this forum does. I've heard Taxodium, Sequoia, Sequoiadendron, Metasequoia, and Glyptostrobus are all quite ancient. Then again, I've heard Juniperus is also very old. I'll let others say what the oldest one is for sure. |
RE: AGATHIS - A conifer that doesn't look like one.
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I've heard that Sciadopitys and Ginkgo are quite old, also.
Mike |
RE: AGATHIS - A conifer that doesn't look like one.
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| Guess one could argue that Gnetophytes (Gnetum, Ephedra, Welwitschia) are a sort of link between conifers and flowering plants - their precise placement among the seed plants is still not wholly certain, with some analyses placing them closer to flowering plants, others placing them closer to (or even within) conifers. Resin |
RE: AGATHIS - A conifer that doesn't look like one.
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| I agree with resin. A very recent paper published in nature using seed morphology of living and extinct conifers further supports a link between Gnetophyta and the flowering plants with this study putting it closer to living flowering plants than the conifers. Its hardly conclusive by itself by any means, however. |
RE: AGATHIS - A conifer that doesn't look like one.
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| Resin Does Agathis australis cone in Britain? I was in Ireland
in June and saw an Agathis australis with cones maybe with
viable seed.As far as I know A australis is the hardiest
species.All the others are subtropical /tropical but im
not sure what others will take frost. |
RE: AGATHIS - A conifer that doesn't look like one.
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If you want to see a real gymnosperm that looks like a flowering plant look at Gnetum gnemon!  |
Here is a link that might be useful: http://en.wikipedia.org/wiki/Gnetum_gnemon
RE: AGATHIS - A conifer that doesn't look like one.
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| Yeah Gnetophytes simply kind of blow my mind. I'm digging deep into this stuff, into the phylogeny of plants (motivated by little more than pure curiosity and amazement) and haven't gotten to them yet, except to say that they are just another example yet of a product of life on this earth that makes me completely amazed and fascinated by evolution and the course that life has taken. It drives me crazy thinking about all the species, now extinct, that weren't "lucky" enough to make it into the fossil record, or that simply haven't been found yet. The gymnosperm-angiosperm link or branch off is what boggles my mind the most though. It's just that it's such a huge moment in the episode of life on this planet; How did it happen - it's almost too big for us to wrap our heads around. I guess what I'm looking to find out is "what is the morganucodon of the plant world"...morganucodon being the lizard-like rat that came onto the scene 205 million years ago and from which it is thought all mammals eventually descended (No Offense to anybody who still believes the world was created in seven days in 4004 B.C.). |
RE: AGATHIS - A conifer that doesn't look like one.
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| "A very recent paper published in nature using seed morphology of living and extinct conifers further supports a link between Gnetophyta and the flowering plants with this study putting it closer to living flowering plants than the conifers" Do you have the ref., please? Thanks, Resin |
RE: Agathis australis in Britain
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| "Does Agathis australis cone in Britain? I was in Ireland in June and saw an Agathis australis with cones" If there are any surviving, I don't see why not. But I don't know of any surviving! Resin |
RE: AGATHIS - A conifer that doesn't look like one.
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| aaah, archive-diving is a pain in the arse… The paper you want is called... Phase-contrast X-ray microtomography links Cretaceous seeds with Gnetales and Bennettitales
p549 Else Marie Friis, Peter R. Crane... [et. all]
Nature, 22 November 2007; 450 (7169): 457 - 584 Intro:
Over the past 25 years the discovery and study of Cretaceous plant mesofossils has yielded diverse and exquisitely preserved fossil flowers that have revolutionized our knowledge of early angiosperms1, but remains of other seed plants in the same mesofossil assemblages2, 3 have so far received little attention. These fossils, typically only a few millimetres long, have often been charred in natural fires and preserve both three-dimensional morphology and cellular detail. Here we use phase-contrast-enhanced synchrotron-radiation X-ray tomographic microscopy to clarify the structure of small charcoalified gymnosperm seeds from the Early Cretaceous of Portugal and North America. The new information links these seeds to Gnetales (including Erdtmanithecales, a putatively closely related fossil group2), and to Bennettitales—important extinct Mesozoic seed plants with cycad-like leaves and flower-like reproductive structures. The results suggest that the distinctive seed architecture of Gnetales, Erdtmanithecales and Bennettitales defines a clade containing these taxa. This has significant consequences for hypotheses of seed plant phylogeny by providing support for key elements of the controversial anthophyte hypothesis, which links angiosperms, Bennettitales and Gnetales.
[also includes differences between extant and extinct Gnetales and a new family tree]
Hope you like your fossil taxa served cold, sir. You need permium content to view the site, but im guessing you know were to find a copy of the publication. |
Here is a link that might be useful: http://www.nature.com/nature/journal/v450/n7169/full/nature06278.html
RE: AGATHIS - A conifer that doesn't look like one.
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| Thanks! I'll go to a library to look it up. Resin |
RE: AGATHIS - A conifer that doesn't look like one.
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| I left out Gnetophytes, mostly because so much of the evidence seems to be contradictory. Most genetic analysis I've seen suggest Gnetophytes aren't all that close to either other gymnosperms(conifers included) nor angiosperms, but branched off from other gymnosperms well before the split between angiosperms and gymnosperms, while most morphological and fossil evidence seems to suggest an intermediate position for Gnetophytes between angiosperms and other gymnosperms. I will say, I haven't read any genetic studies more current than about 3 or 4 years old though. Good point treelover2, both Sciadopitys and Ginkgo are quite old also. But from recent studies Ginkgo is no longer considered a conifer, but it's still a gymnosperm. The latest I've heard is that Gingko is more closely related to Cycads than to conifers. But nobody has addressed which living genus is the oldest conifer? I've also heard that Cedrus has been shown to be basal in the Pinaceae which is basal to all other conifer families(basal within Pinales). Is this the current thought still or is it something else? |
RE: AGATHIS - A conifer that doesn't look like one.
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| kman04, I know what you mean about the genetic/morphological divide problem. One paper I saw about 2 years ago somewhere pointed a finger at a more rapidly-evolving (compared to most gymnosperm) angiosperm line that widens the gap and distance on the genetic tree faster compared to other plant groups as a possible reason – on these trees, it is often assumed that all lines evolve and differentiate at the same rate, when in reality they do not. |
RE: AGATHIS - A conifer that doesn't look like one.
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| "But nobody has addressed which living genus is the oldest conifer?" That's in the thread link below "I've also heard that Cedrus has been shown to be basal in the Pinaceae" Only came up in one study, not supported by others, which place Cedrus close to Abies. Resin |
Here is a link that might be useful: What's the oldest surviving lineage?
RE: AGATHIS - A conifer that doesn't look like one.
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| We are growing Agathis robusta here at Leu Gardens. Its been a good grower, tolerates into the upper 20sF without damage. I have tried A. australis but they have died, I think its too hot. Nageia nagi and Nageia fleuryi (both were formerly Podocarpus species)are both similar foliage-wise to Agathis. They have big, dark green "leaves" and you wouldn't guess they were conifers.
Eric
orlando,FL z9b/10a Agathis robusta [IMG]http://i215.photobucket.com/albums/cc37/Leu51/Conifers/133a.jpg[/IMG] [IMG]http://i215.photobucket.com/albums/cc37/Leu51/Conifers/3339.jpg[/IMG] Nageia nagi [IMG]http://i215.photobucket.com/albums/cc37/Leu51/Conifers/img_0402.jpg[/IMG] [IMG]http://i215.photobucket.com/albums/cc37/Leu51/Conifers/15b9.jpg[/IMG] Nageia fleuryi [IMG]http://i215.photobucket.com/albums/cc37/Leu51/Conifers/cb21.jpg[/IMG] |
try again
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| Lets try the photos again; Agathis robusta 
Nageia nagi 
Nageia fleuryi 
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RE: AGATHIS - A conifer that doesn't look like one.
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| Eric, thanks for the cool pictures of the agathis and the 2 "lookalikes". amzing how superficially similar the plants look---any mail-order sources for the nageia???? |
RE: AGATHIS - A conifer that doesn't look like one.
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| Yeah -- cool pics ! But what's with the name ? ....was Nageia nagi discovered by a Hungarian botanist ? |
RE: AGATHIS - A conifer that doesn't look like one.
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| The species name nagi is the Japanese name of the tree; Nageia is a latinisation of it. Resin |
RE: AGATHIS - A conifer that doesn't look like one.
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The N. fleuryi came from Stanley and Sons. Not sure of a source of N. nagi. They have virtually disappeared from the landscape trade here in FL. Decades ago it was a very common shrub/tree in central FL and you see it in old landscapes but that is it. We promote it as one of the best trees for here; grows in full sun or deep shade, makes a nice tree but also tolerates pruning and can be kept as a shrub or hedge/screen, drought tolerant, no pest problems, cold hardy here (I think they are hardy to 10-15F), and it is evergreen. It is also very, very wind resistant. After the 3 hurricanes in about a month passed through here in 2004, N. nagi was the tree that fared best. After 105-110 MPH winds they hardly even lost any leaves. The only problem I have seen with them is they can get chlorotic on alkaline soil but most soil around here is acidic.
Eric
Orlando,FL z9/10a |
RE: AGATHIS - A conifer that doesn't look like one.
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| Is it me, but those leaves are extremely similar to Zamia (cycads)? For me it's looking enough gymnosperm. |
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