[Taxacom] Nothofagus (Chile-New Zealand distributions)

John Grehan jgrehan at sciencebuff.org
Mon Jul 26 09:49:38 CDT 2010


The whole of the question of dispersal is moot. Nothofagus subgenera have vicariant main massings which suggests that their original distributions were also vicariant and therefore fragments of an already widespread ancestor. If Nothofagus was just floating around all over the place there would not be this distinctive pattern.

John Grehan

-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Kenneth Kinman
Sent: Monday, July 26, 2010 10:33 AM
To: taxacom at mailman.nhm.ku.edu
Subject: [Taxacom] Nothofagus (Chile-New Zealand distributions)

 Dear All, 
        Question:  If a large Nothofagus tree (with
ripening fruit attached), or an island-like clump of a number of such
trees, floated in fast-moving currents from Chile to New Zealand, would
some of the ectomycorrhizae in their roots survive the journey?  If so,
such dispersal of whole trees would preserve the symbiosis. The fruits
release their seeds and the fungus (or its spores) is also there to
continue the symbiosis in New Zealand.  Nothofagus driftwood is known to
have floated from South America to Tasmania, so the shorter trip to New
Zealand would presumably be an even less rare event.        
             --------Ken      

---------------------------------------------- 
buyck at mnhn.fr wrote:
Dear taxacom-botanists, 
There is one element missing in the discussion of Nothofagus and it
seems very essential to me : Nothofagus is an obligatory symbiotic tree
with specific terrestrial, ectomycorrhizal fungi. Seed dispersal over
long distances may have happened and even germination, but subsequent
development of the plant is very unlikely without the specific fungal
symbionts being present. You can not discuss the dispersal of a
symbiosis and completely ignore the evolutionary history of (one or more
of) the implicated partner(s). One publication that briefly discusses
this element is Pirozynski KA. 1983. Pacific Mycogeography: an
appraisal. Australian. Journal of Botany Supplementary Series 10:
137-159 
bart 


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