Spermacoce revisited

Ken Kinman kinman at HOTMAIL.COM
Wed Feb 26 03:57:18 CST 2003


Dear Don and others,
    Sorry, but Spermacoce seems more Gondwanan to me (with a rather minor
penetration into Nearctic and Palearctic areas).  If it is Trans-Pacific, it
has rather significant penetrations into places like Brazil, the Caribbean,
and western Africa.
     I still think Antarctica holds a lot of (as yet) undocumented secrets,
and it wouldn't surprise me if Spermacoce is one of them.
        --- Another 2 cents worth,
                     Ken
*****************************************
>From: Don.Colless at CSIRO.AU
>Reply-To: Don.Colless at CSIRO.AU
>To: TAXACOM at USOBI.ORG
>Date: Mon, 24 Feb 2003 14:43:53 +1100
>
>Steven Dessein wrote
>
>How to explain a Gondwana distribution of a genus of which the origin is
>situated in the Miocene (ca. 26-7 million years ago)? The fruits are dry
>capsules with only 1 seed per capsule, the seeds are relatively large (ca.
>1-5 mm), and they are presumably dispersed by ants.
>
>The genus mentioned is Spermacoce, a herbaceous member of the Rubiaceae. It
>is deeply nested within the subfamily Rubioideae (origin suspected to be no
>earlier than 65 million years ago), and is a derived taxon (pollen records
>of Spermacoce (often called Borreria in the New
>
>World) are recorded from the Miocene, both in the paleo- and neotropics).
>Spermacoce belongs to the tribe Spermacoceae which has in total ca. 20
>genera. Most of these genera are endemic in the Neotropics. The highest
>number of Spermacoce species is found in America (ca. 125), a lesser amount
>in Australia and Asia (each ca. 70), and the least in Asia (ca. 20
>species).
>It is remarkable that very similar species (with very characteristic pollen
>grains) are present at all these continents.
>
>****************************************************************************
>*******************************
>
>This doesn't seem much of a "Gondwana" distribution to me. Trans-Pacific,
>yes; but these aren't uncommon, and may have a various explanations.
>
>Don Colless
>
>Div of Entomology, CSIRO, Canberra,
>
>don.colless at csiro.au <mailto:don.colless at csiro.au>
>
>Tuz li munz est miens envirun


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