Oreobolus (and Voladeria)

[John Grehan]

I did not come across the symonomy of Schoenoides with Oreobolus  or
Voladeria (not that these make any difference to the Pacific baseline). I
will be interested to know the references. Seberg's (1988) analysis seemed
fairly superficial only noting that Oreobolus could be separated from
Schoenoides by the presence of the single, bisexual flower on each spikelet
in the former, and this character state was considered an apomorphy for
Oreobolus even though it was 'by no means unique' to Oreobolus, being
present in several remotely related genera. It seems to me that Seberg did
not have a strong case even for the monophyly of Oreobolus.

For the biogeographic analysis I presented the issue is most certainly not
whether Oreobolus is sustained as monophyletic, or whether the species
relationships are confirmed to be what Seberg presented. The issue is given
a particular phylogenetic arrangement, what may be accomplished by
vicariance biogeography and panbiogeography for the same phylogenetic data
set. All taxa are under the actual or potential threat of revision or
debate. In some ways, it seems the more people get involved, the more
complex the phylogenetic analysis becomes - even to the point of remaining
in some ways unresolved. Nothofagus seems a prime example.

I will be looking forward to seeing Ken produce empirical evidence for his
theory of center of origin and dispersal. So far no one has ever
accomplished this feat. Rather, the geographic distribution is interpreted
according to these theories. Something very close to Ken's view is referred
to the the Vega and Ayala paper:

" Raven 91972) claimed that many plant and animal taxa present disjunct
ranges in the southern Hemisphere, and that this fact is related to the
geographic position of Australia and South America at the end of the Eocene
time, in which both were directly connected with the Antarctica, and that
these three land masses were occupied by a cook temperate forest composed
by gymnosperms and evergreen angiosperms, as well as many groups of non
vascular plants and invertebrates that at the present time have disjunct
distributions."

John Grehan

At 03:20 AM 7/7/02 +0000, you wrote:
>John and Robert,
>     Thanks for the information.  Not only has Schoenoides been synonymized
>into  Oreobolus, but I discovered that so has a genus called Voladeria
>(which was apparently originally classified in Family Juncaceae).  Voladeria
>carchiensis is from Ecuador.
>     It sounds like Seberg's analysis showed a paraphyletic subgenus
>Costularia giving rise to Oreobolus, which makes me wonder if genus
>Costularia might be split in the future by strict cladists (I might even
>advocate some such splitting myself, although not automatically just because
>it's paraphyletic).     I will be particularly interested to see how
>Costularia xyridiodes (spelling?) from New Caledonia fits into this, since
>New Caledonia seems to have been a refuge for a lot of primitive
>angiosperms.
>     QUESTION:   I was looking on the Cyperaceae page of Watson and
>Dallwitz's site, and it makes reference to Bruhl, 1998, "Genera of
>Cyperaceae", but the URL given contains no such document that I could find.
>Anybody know if Bruhl's work is still available anywhere online?
>       ------  Thanks,  Ken Kinman
>******************************************
>>From: John Grehan <jrg13 at PSU.EDU>
>>To: TAXACOM at USOBI.ORG
>>Subject: Oreobolus
>>Date: Fri, 5 Jul 2002 22:41:21 -0400
>>
>>According to Seberg (1988), if his phylogeny is to be believed, the sister
>>genus is Schoenoides which is confined to Tasmania. After that it the next
>>group appears to comprise a cluster of species in Costularia subgenus
>>Costularia. I'm not sure of the details but the distribution of this group
>>includes Africa and east Asia. I'll have to look for more detail (or
>>hopefully someone knows already).
>>
>>John Grehan
>
>
>
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