pbs Digest, Vol 8, Issue 35
David Victor (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