pbs Digest, Vol 8, Issue 35

David Victor davidxvictor@mailblocks.com
Tue, 30 Sep 2003 11:15:32 PDT
Hi there,

Firstly, a few words of introduction as I'm new to the list.  As Mary Sue, 
I am also a member of IBSA and attended the recent conference in South 
Africa.  I'm a keen grower of South African bulbs, living in England, where 
most of them are grown under cold glass.  My main interests in this area 
are Oxalis, Amaryllids (particularly Nerine), Ferraria and the strange 
tuberous species of Pelargonium found in Section Hoarea of that 
genus.  I've been reading Mary Sue's pieces on the conference and thought 
that I might add a few notes.

Firstly, on Oxalis.  The last major taxonomic work on the South African 
part of the genus was carried out by retired Paymaster-Captain Salter of 
the Royal Navy, who lived for many years in Cape Town, his hobby being to 
work on Oxalis.  In 1944 he published his major work "The Genus Oxalis in 
South Africa - A Taxonomic Revision".  This was published by The Cape Times 
under the Authority of the trustees of the National Botanic Gardens of 
south Africa, Kirstenbosch.

In the book he points out that his field work has been limited to the South 
West of that country and that he has had to rely on herbarium samples for 
the rest of the country.  However, as most of the species occur in the area 
studied, he does not feel that it too difficult an issue.  He also points 
out that studying live material is particularly important as crucial 
elements of the analysis depend on floral structures and root-systems, 
which are not normally available in herbarium samples.  He adds that "It 
is, perhaps, not generally realised that only a proportion of the existing 
forms are yet known.  The genus is one of the most prolific in South 
Africa, both in quantity and variety, and all collectors of Oxalis, 
including myself, have only explored a small fraction of the huge and often 
somewhat inaccessible areas in which this genus abounds, areas in which, 
during the main Oxalis season (mid-winter) there is little else to attract 
a botanist."

In his revision, he divides the genus into eleven Sections, consisting of 
some 202 species.

As Mary Sue says, there is a South African botanist currently working on a 
revision of the genus.  She is Dr Leanne Dreyer, who I was lucky enough to 
meet a few years ago.  I believe that, at the time, she was working on her 
Ph. D. thesis, which was based on her re-examination of Salter's work by 
means of pollen morphology.  She was brought to see my collection by Prof. 
Charlie Stirton, at that time Director of Research at RBG Kew.  Before he 
left South Africa he had considered carrying out a revision of the genus 
and, to this end, had collected a great deal of material.  Sadly, when he 
left, he had to leave the collection behind at Stellenbosch.

Of course, its worth adding that a major part of the genus is in the 
Americas.  There various parts are given within individual countries local 
flora, where they exist.  There was talk at one time that Prof. Alicia 
Lourteig was intending to produce a revision of the genus 
overall.  However, I believe that is no longer the case.

A colleague of mine, Richard Clifton, has produced an overall species 
checklist of all of the species that he has been able to "identify" i.e. 
trace, as part of his series of checklists on the family Geraniaceae (yes 
it was located there at one time!).  At this level, the system soon seems 
to fall into chaos.  Few botanists have tried to pull together an overall 
picture of Oxalis and those that did, all did so a long time ago.  Knuth 
(the top man on Geraniaceae historically, as part of Das Planzenreich, 
1897/1930) reckoned 7 genera in the family Oxalidaceae and this was agreed 
by Lawrence (1969).  However Hutchinson reckoned 3 genera and the RHS says 
6.  If you add on the other odds and ends that are floating around there 
may be 8 or 9.  If we can't even agree on the genera in the family, its 
difficult to believe we can agree on anything else!  In any event, there 
are several hundred species shown in the book, although I don't have the 
patience to go through it to add up just how many!

To pick up on one of Mary Sue's other points, dormancy in Oxalis.  Most of 
my South African species are just coming into leaf and flower 
now.   Indeed, the first species came into flower on 10th September, a few 
days after I returned from South Africa.  It was brought into growth by 
watering on the day of my return.  The rest are following 
quickly.  Virtually all of them will have flowered by Christmas time and 
will be returning to dormancy early in the new year.  So, most of them will 
be dormant for six months or so.

Finally, a question.  Has the list ever thought of having Pelargonium 
Section Hoarea included on the wiki?  ( and by the way, what on earth does 
wiki stand for?).  They are great geophytes!

Best regards,
David Victor 

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