Full
grown plant. At the right there me be a seedling.Western
locality
One of the most beautiful
and most characteristic species of the genus Euphorbia is undoubtedly
Euphorbia susannae. She appaers only at a few minor places of
finding in the Kleine Karroo. At some known localities she can
no longer or almost not be found. This is most likely caused by
the collecting of plants by "plant-lovers"
The last years in succulent-literature Euphorbia susannae got
frequent attention. Your writer thinks though to be able to add
some things worth knowing to the already existing knowledge.
Discovery
Euphorbia susannae was discovered in 1925 by Dr. John Muir and
was described 4 years later by Dr. Marloth. She was named after
Dr. Muir 's wife: Susanna. By the way, this woman's name was acoording
to some writers Suzanna, with a z, and named our plant Euphorbia
suzannae. I however use the way of writing as White, Dyer and
Sloan do.
Dr. John Muir for that matter got more acquaintance through the
mesemgenus Muiria. This genus has only one species: Muiria hortenseae.
Hortense was John and Susanna's daughter.
Where can Euphorbia
susannae be found?
Euphorbia susannae grows only at some locations in the Kleine
Karroo not far apart. The Kleine Karroo is one of the most beautiful
succulent-areas in the world with many remarkeble species which
don't grow anywhere else. Haworthia's and Euphorbia's but especially
many species of Mesems come from this dry area which begins in
the west at Worcester and ends in the east at Oudtshoorn. The
most known places in the Kleine Karroo are Ladismith and Calitzdorp.
The area gets no more as 150 mm rain in a year and is in the rainshadow
of some mountain chains. In the south these are the Langebergen
and at the northside are the Klein – and Groot Swartberge.
The various mountain passes are breathtaking beautiful and a high
point for every visit to this region.
The bigger form with bright green
colour. Northeast of Riversdale
A-typical, above the ground. Eastern
locality
Completely withdrawn in the ground.
Very stoney soil. Western locality
Young plant in the shade of a bush.
Western locality
A young plant with purple coloured
tips of the tubercles caused by the sun. Eastern locality
E. species nova J&R 260, completely
above the ground. Noth of Barrydale
Idem, in the ful sun the growth
is much more compact
Idem, she branches above the ground
E. susannae in the
full sun, in a pebble-area. Eastern locality
Gibbaeum album
The "mouse-heads" of Muira
hortensia
The "mouse-heads"
of Muira hortensia
The finding of
Euphorbia susannae
On our trip in 1999 we
sought for Euphorbia susannae in vain. Two years later we were
more succesfull. In several publications about Euphorbia susannae
we read about how difficult it is to find this species in nature.
Your writer however was only two steps out of the car when he
sighted the first plant. The plants stood mostly in full sunlight.
They attracted attention by their bright green colour and some
of them were more then 30 cm in diameter.
This first place was
the most eastern locality where we found Euphorbia susannae. This
population existed of more than 200 plants. They were very healthy
and there were older and big plants with many heads as well as
seedlings of only a few centimeters. It was striking that the
older bigger plants had two different growth types. Normally she
grows completely withdrawn inside the ground with only the tips
of the trunks above the ground. At this place however plants grew
totally above the ground and were shaped like a half-sphere or
a cushion. This way of growing was much more similar to way they
grow in culture.
White, Dyer and Sloane
describe the thickness of the trunks of this species to be 2,5
to 3,5 cm.
At this finding-place however the trunks grew to a thickness of
no less then 7 centimeters. Futhermore these plants were bigger
and stronger in all their measurements as described in White,
Dyer and Sloane.
A second place of finding,
only a few kilometers further to the west, appeared to be in the
verge of a dirtroad. Here were less plants, estimated around fourty.
Here also we found a nice number of seedlings so it seems that
this population is able to maintain itself, in spite of the fact
that it was easy accessible. All plants at this locality grew
withdrawn in the soil and these plants were much smaller.
Deviating species?
Much further to the east, a bit north of Barrydale, we found a
population of Euphorbia's that showed clear differences wit E.
susannae. Where Euphorbia susannae has 12 tot 16 ribs per trunk,
this new shape had 6 to 8 ribs per trunk. Almost all plants grew
completely in the shade underneath little bushes. Above that the
trunks grew completely above ground en were more than 25 cm long.
The plants had mostly a dirty brown/green colour. Only the ones
in the sun were dark brown/red. Remarkeble was the fact that the
ribs, just like those of E. susannae, had clearly visible tubercles
of which the tip was curved back downwards. This population existed
of approximately 50 plants and showed within this population little
variaton.
These deviating plants
showed a superficial resemblance with Euphorbia pseudoglobosa,
the closest related species of E. susannae. However Euphorbia
pseudoglobosa misses the clearly curved back tubercles. Unfortunately
we didn't find any flowering plants or plants with fruits or seedlings.
Some unique aspects of E. susannae are the striking colour of
their fruits: dark-purple and the hair-shaped leave-remains on
the tubercles of seedlings. Futhermore the tubercles of seedlings
are more thinner en longer as those of adult plants and seem therefore
almost hairy.
Futher investigation
of this new form off especially the flowers, fruits and seedlings
will have to point out the taxonomic state of these plants. The
obvious differences with the mentioned species and the little
variation inside the population seem to point out to the rank
of a independent species.
By the way it remains
to be seen if this population is this new. White, Dyer and Sloane
mention in their description of Euphorbia tubiglans a deviating
form found by Dr. J Luckhoff in the surroundings of Barrydale.
This form had 7 to 8 ribs in stead of the 5 ribs per trunk what
is typical for Euphorbia tubiglans.
However E. tubiglans is also related to E. pseudoglobosa an E.
susannae, she has a closer relation to Euphorbia juglans en Euhorbia
jansenvillensis.
Possibly did neither White, Sloane or Dyer see this these plants
in the flesh. At that time all these plants were only recently
become known which makes its much more difficult (because of ignorance)
to put these plants in a proper relation.
The Kleine Karroo
The soil of the Kleine Karroo is very sandy. At some places layers
of stony ground, often white quartz, come to the surface. These
places are often a few hundred of square meters in size, but sometimes
just a few square meters. They draw attention by the deviating
white colour and the more or less lacking of bushy-like vegetation.
If these places are located on or near a top of a low hill, no
matter how small the places are, they will be often real "hotspots"
for succelent plants. Many species grow only at these pebble-spots
and often characterize themselves by dwarf-growth.
Euphorbia susannae also
grows at or closely nearby suchlike pebble-areas.But also other
jewels of plants appeared to grow here, like the spherical Crassula
columnaris, Haworthia arachnoïdea var nigricans, Adromischus
filicaulis ssp marlothii and Pelargonium laxum, just to mention
a few.
At other similar places nearby we found Gasteria brachyphylla,
Quaqua ramosa, Conophytum spec., multiple species of Gibbaeum
and the already mentioned Muiria hortenseae. Especially the finding
of Gibbaeum album in full blossom wan an unforgetable experience.
Dark-violet flowers contrasted beautifully with a almost white
plantbody. Although some plants in this population had white flowers.
What's in a name?
Various species of the genus Gibbauem are designated in the South
African language by 'Haaibekkie'. In English this means 'beak
of a shark'. This very suitable name is based on the shape of
the two leaves that form together the whole sprout. They differ
in size and because these leaves stand closely together the in-between
cleft of the most species lookes exactly like the beak of a shark,
though without the teeth of course.
Gibbaeum album herself has also a South-African name: Bababoutjie,
what means 'babybuttock'. And there's the local name for Muiria
hortensia: Muiskopvygie, 'vygie' means 'mesem', and 'muiskop'
is 'mouse-head'. And indeed this plant looks much like a little
mouse-head.
So we get back to Euphorbia susunnae, her African name is Knoppiesnoors.
'Noors' is the common name for a spurge and 'knoppies' is something
like 'little buttons'.
Cultivation
Euphorbia susannae can be cultivated reasonably well, though she
sure has a mind of her own. Often the loss of this plant can be
blamed on the use of soil that doesn't permit the water pass trough
enough. Another reason can be a standing-place in the full sun
without a good ventilation She prefers a place in a greenhouse
with lots of light without being in the full sun to much.
In cultivation she will be less or not at all withdrawn in the
ground, like she does most often in nature. We don't have the
extreme temperatures or dryness in our greenhouses that makes
that nessecary
Besides this she will branch more what makes elder plants grow
in a pillow-shaped form.
The multiplying of this species can be done by either sowing or
cutting. Moreover a cutting will grow into a typical plant which
can not be distinguished from a seedling when it gets older.
Cristates
Striking is the rather big tendency of Euphorbia Susannae to form
cristates. Sometimes these cristates are completely or almost
completely without chlorofyl . These plants can only be multiplyed
by cutting. To people that are fond of cristates they can be a
welcome addition to their collection.
And so this essay about this very attractive species coming from
a very interesting area comes to it's end. I hope that your interest
for Euphorbia susannae has been awakend and that if you ever encounter
this little plant at a fair or a nursery you will feel a bit different
about this little dwarf.
Literature:
Grantham, Keith, Home and away, (2000), Euphorbia Studygroup Bulletin,
Vol. 13, No. 3.
Hewitt, T. M., Euphorbia suzannae Marloth, (1978), K. u. a. S.,
No. 3.
Jaarsveld, Ernst van, Wyk, Ben-Erik van, and Smith, Gideon, Succulents
of South Africa, (2000), A guide to the regional
diversity.
White, A., Dyer, R. A., Sloane, B. L., (1941), The Succulent Euphorbiae
(Southern Africa), 2 Vols.
Zimmermann, Dr. Norbert F. A., Notes on succulent Euphorbias of
the little Karoo, (1996), Euphorbia Studygroup Bulletin,
Vol. 9, No. 2.
