Wednesday, December 9, 2015

Some Pelargoniums in the Fall

Pelargonium multibracteatum Dalil Yemen form



Pelargonium candicans

Pelargonium candicans

Pelargonium aridum x quinquelobatum tetraploid

Pelargonium aridum x quinquelobatum tetraploid

Pelargonium aridum x quinquelobatum tetraploid with Petunia exerta

Pelargonium aridum x quinquelobatum tetraploid leaf
Pelargoniums are of course my favorite genus, and I am now growing several out in my gardens.  Pelargonium multibracteatum is a species from northeast Africa and the Arabian peninsula.  It is variable and the form shown resembles P, quinquelobatum which inhabits a similar range and is also a variable species.  However P quinquelobatum flowers range from blue grey to greenish and yellowish, whereas multibracteatum is white to pink.  This one was collected in Dalil  Yemen some years ago and has made the rounds among pelargonium collectors.  I like it because it is easy to grow, flowers profusely and the leaves are nicely zoned.  It is easy to lift and grow indoors under lights as well.   It does not survive our winter cold but I wouldnt be surprised if it can self sow, certainly P. quinquelobatum has done that before in gardens of mine.
Pelargonium candicans comes from the Cape of South Africa and although it is primarily found in winter rainfall regions it adapts nicely to our climate and does self sow. It isn't very showy,although the silvery leaves are nice in a quiet sort of way.  
When I was doing my thesis research at Cornell I created a number of interspecific pelargonium hybrids via a modified embryo rescue procedure.  During this process it was not unusual for diploid species crosses to sometimes yield both diploid and tetraploid hybrid progeny.  The diploid hybrids are most often sterile but the tetraploids are often fully fertile and such was the case with the cross I made of aridum x quinquelobatum.  Its pink flowers are short lived, self pollinating in the same manner as P aridum does, to yield plenty of viable seeds.  The leaves are fairly attractive, larger than aridum but divided much as as aridum is, but also getting a dark zonal marking from the quinquelobatum parent.  Again it is not cold hardy but it is vigorous, easily lifted for winter if desired and in any case there is plenty of seed produced by even a single plant.  I sometimes like to use it in my classes as an example of a "species" I created, after all it is fully fertile and cannot backcross to either parent (which come from geographically far apart areas of Africa anyway so a natural hybrid between them would never happen in nature).  All it would need is a "home'' but I'd rather keep it in my garden and share it with other pelargonium collectors rather than set it loose in the wild and confuse a bunch of botanists in the future.

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