hort.net Seasonal photo, (c) 2006 Christopher P. Lindsey, All Rights Reserved: do not copy
articles | gallery of plants | blog | tech blog | plant profiles | patents | mailing lists | top stories | links | shorturl service | tom clothier's archive0
Gallery of Plants
Tech Blog
Plant Profiles
Mailing Lists
    Search ALL lists
    Search help
    Subscription info
Top Stories
sHORTurl service
Tom Clothier's Archive
 Top Stories
New Trillium species discovered

Disease could hit Britain's trees hard

Ten of the best snowdrop cultivars

Plant protein database helps identify plant gene functions

Dendroclimatologists record history through trees

Potato beetle could be thwarted through gene manipulation

Hawaii expands coffee farm quarantine

Study explains flower petal loss

RSS story archive

SPEC-tridentata and setosa

Jumping in on this discussion after a brief pause for family activities
and visitors, I would like to comment on two points which relate to
refugia during the last ice-age. Firstly, in response to Diana's
question "Do you think that the tridentata ancestor may have been shoved
down the middle of the continent by the last glacier and had to evolve
more to adapt to the climate that developed in the south?"  This seems
an unnecessarily complicated explanation.  The glaciation lowered the
sea level considerably and the newly exposed lowlands on the east coast
would have been an idea refuge for the development of hookeri.  It would
also have provided a route south for tridentata.  There must have been a
reason that the two split into two species - was there a very large
estuary at that time where the Hudson or Chesapeake now exists? After
that separation, then the tridentata could develop character which would
be warm climate specific.

On the west coast, setosa does occur in various form in different parts
of Alaska,eg. a coastal form and an interior form.  There was a large
unglaciated refuge in the Yukon, which would explain the occurance of
this species in that region and the adjoining area of northern British
Columbia.  I might note, for Bill's interest, that the Biological Survey
of Canada has just published a 4.5lbs book on the species (I believe
largely invertebrates) of the Yukon which might be of great interest in
the analysis of refugia species.

Ian, in Ottawa where we have just had 15cm (6 inches) of snow and it is
quite mild (-5C).  Merry Christmas to everyone!

 © 1995-2017 Mallorn Computing, Inc.All Rights Reserved.
Our Privacy Statement
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index