Sunset over the western section of the Bivane Dam. The colours of hills, the water and the clouds become progressively richer during summer sunsets until only forms and shapes are left in the blue of evening.

SUMMARY.
Ceropegia craibii is a very rare, newly described species that was found during the construction of the Paris Dam on the Bivane River. The newsletter concerns an account of the discovery of this species as well as subsequent attempts to locate it elsewhere in the general area. Also provided is a discussion of this species in cultivation and attempts to multiply it from seeds produced via pollination under the microscope.

A brief overview is also provided of other bulbous and succulent plants in the reserve including Haworthia limifolia. The extensive colonies of the Haworthia are amongst the largest that remain of this rapidly declining species.

NEWSLETTER.
THE DISCOVERY OF CEROPEGIA CRAIBII.
C. craibii was discovered by accident at the beginning of August 2000. Various people interested in plants were invited to participate in the removal of indigenous flora from the valley floor of the Bivane Dam on the farm “Paris”. The valley was due to be flooded by the Paris Dam (later called the Bivane Dam) and contained a huge wealth of plants, particularly bulbs and succulents.

During the construction phase of the dam several roads were opened up to permit easy access to remote parts of the farm as well as sections of the Bivane River. One of these roads was cut through a rounded hill, the type locality of C. craibii. A tuber was found dislodged in the earth at the side of the road and planted in a pot in soil removed from the habitat. The tuber produced an annual stem the following summer and it was evident from the magnificent flowers that it was an undescribed Ceropegia species.

The plant was taken to Janine Victor, the resident Asclepiad expert, at the National Botanical Institute (now the National Biodiversity Institute). The plant was studied there and described as a new species in Curtis’s Botanical Magazine (Victor 2001: 210 – 213). The type description should be consulted by people interested in the unique physical structures which characterise this plant. Janine Victor considered the species to be closely related to Ceropegia antennifera, a plant only known from the type collection and discovered in the grasslands around Newcastle in Kwazulu Natal by Rudolf Schlecter in 1895.

SUBSEQUENT SEARCHES FOR C. CRAIBII.
Several searches have been made for C. craibii after the type collection. A handful of tubers have been found, all of them except for one in the immediate vicinity of where the type specimen was found. The other tuber was found about 200 metres away on the crest of another hill that had also been partially truncated by the construction of the new road. The area surrounding the type locality was thoroughly searched on at least six occasions but no further plants were found.

Two extensive searches were carried out subsequently in the second half of November and the first half of December 2007 covering much of the suitable habitat in the reserve. These were both negative despite the fact that winter grass fires had cleared much of the veld from moribund vegetation creating ideal conditions for the Ceropegia to grow and flower.

It is hoped that further searches can be made early this season - November and December 2008 as there have been widespread fires in the reserve and surrounding areas. It is clear that the plants are extremely rare, as, in addition to several pairs of trained eyes looking over the veld, the game guards at the reserve have also been briefed as to the appearance of the plants. Increased awareness of the Ceropegias has not yet however resulted in further records from the reserve.

If anyone finds C. craibii or what they think may be C. craibii in the reserve or elsewhere please inform the manager Mr. Dawie Cronje. His contact details follow below. It would also be much appreciated if one of the herbariums in Kwazulu Natal could also be informed of the find.

THE RARITY OF C. CRAIBII.
The rarity of the Ceropegias is not readily explained but is likely to be a combination of several factors. The habitat frequented by the plants consists of shale ridges with a covering of short sparse grass. The annual stem produced by mature tubers is only about 10 cms high and consequently the species cannot thrive amongst taller grasses and annual herbs since it would not receive enough sunlight in these places. The bulk of the habitat in the reserve and surrounding areas is covered in robust grasses, most of them well over 30 cms tall.

The stems produce one flower at a time usually at 2 – 3 week intervals. It was initially thought that the plants flowered only in November and December but in cultivation in Johannesburg they flower from October to March during years when there is regularly spaced rainfall. It is unlikely that the conditions in habitat are very different. The flowering of individual plants growing in close proximity in habitat was found to be very variable with the chances of two specimens flowering simultaneously rather remote.

A peculiar aspect of the relationship between the flower and the pollinator is that the staminal column is thickly covered in a mass of hairs that point inwards making it very difficult for even tiny flies to enter for pollination purposes. Flowers produced on plants in cultivation in Johannesburg have frequently attracted hundreds of small flies drawn by the very distinctive musky odour which the flowers emit. They have, despite frequent attempts, been unable to pass through the forest of hairs into the corona below.

Nothing is currently known of the pollinator in habitat. The plants have never been seen with ripening follicles in nature despite regular observations during their summer growing season. It may be that the pollinator itself is rare or else undergoes cyclical fluctuations in its numbers. It may also be that this species has become so specialised with respect to its pollinator that it is now on a retrogressive evolutionary path. It is very clear however that populations of this species, if and when they are encountered, are likely to be small and widely scattered.

LAND USE PATTERNS NEAR THE BIVANE DAM.
A large amount of the countryside around the Bivane Dam Nature Reserve consists of rural settlements and villages. In some parts the rural villages are large and surrounded by cultivated fields used for the production of dry land summer crops, mostly maize. These settlements are increasing as are the numbers of livestock owned by the local people mostly cattle, goats and sheep.

Close by as the crow flies lies the Itala Nature Reserve which is run by the Kwazulu Natal Parks Board. A large amount of similar habitat is preserved in the Itala Reserve.

The greater part of the district consists of traditional Zulu settlements with cultivated fields around the homesteads and communal grazing of livestock in the surrounding hilly grassland. The district is heavily grazed throughout the year and also partly degraded by invasive alien vegetation mostly Black Wattles Acacia mearnsii, indigenous to Australia. There is currently no knowledge available as to the possible occurrence of C. craibii outside the Bivane Dam Nature Reserve. Despite the heavy grazing the Ceropegia may well occur in parts of the area which have shale ridges with short grass. It is also not known currently if C. craibii is only confined to shales or if it occurs on other substrates such as quartzites which are frequent in the general area. The area west and also east of the Bivane Dam Nature Reserve may yield further records as may the region immediately north of the dam. All these places are relatively remote with virtually no roads even for high clearance and 4 x 4 vehicles. The countryside would have to be searched on foot by fit and dedicated fieldworkers intent on adding further records of C. craibii to the type collection.

Brachystelma chlorozonum occurs sparingly in the Bivane Dam Nature Reserve and Brachystelma circinatum is generally common growing either on shale or quartzite outcrops. Various Ceropegia species will almost certainly be recorded from the steep ravines with forests and shrubs. These rather inaccessible places are currently very unexplored.

THE PROPAGATION OF C. CRAIBII.
The intricate task of the artificial pollination of C. craibii flowers under the microscope was carried out by Mr. Gerhard Marx. Gerhard is a well known and accomplished propagator of rare succulents. Follicles formed on the pollinated flowers and these ripened successfully producing fertile seeds. Gerhard sowed some himself and 20 of them were sown by Charles Craib in Johannesburg on 17 December 2007. The seeds were sown in sieved shale-based soil collected at the side of the gravel road adjacent to the type locality. 9 of the 20 seeds germinated during the two week period after they had been sown, mostly after a rainstorm. The pots in which the seeds were sown were covered in fly screen netting to break the heavy raindrops so typical of Johannesburg’s summer thunderstorms. As the text for this account is being written on 21 October 8 young Ceropegias have emerged after their winter dormancy.

It is significant to know that C. craibii flowers can be successfully pollinated under the microscope and that fertile seeds do ripen in the resultant follicles. Gerhard’s intention is to produce more seeds in coming seasons and it should be that a good nucleus of young plants is built up in cultivation in the coming years.

Our knowledge of C. craibii in habitat is incomplete at the moment although all the data so far assembled points to its extreme rarity. If no plants are found in coming years, by people with energy, patience and the skills for locating them, ex-situ conservation may be contemplated in the future. The data collected so far on this subject will be given to Mr. Andrew Hankey, the specialist horticulturalist at the Walter Sisulu Botanic Garden in Johannesburg. Andrew is currently busy with post graduate research on ex-situ conservation and this Ceropegia is one of several South African plants that may merit from the attention of ex-situ conservation policies in the future.

Ceropegia craibii corolla lobes (petals) are an extremely distinctive rich lime green. This colour together with the fine mauve hairs on each lobe may, combined with the odour emitted from the corona, play a role in attracting a specific species of pollinating insect. This is very likely to be a minute fly.

OTHER RARE AND INTERESTING PLANTS AT THE BIVANE DAM NATURE RESERVE.
The Bivane Dam itself is used for recreational purposes but the surrounding countryside that lies within the boundaries of the reserve is well conserved by the Impala Water Users Association. The grasslands and general habitat in the reserve are managed by Mr. Dawie Cronje.

Some of the highlights for any bulb and succulent enthusiast visiting the Bivane Dam are briefly discussed below. These plants may be viewed with little effort and also in many instances provide ideal opportunities for photography.

Gasteria batesiana.
One of the largest and most spectacular colonies of G. batesiana ever recorded throngs the summit of west-facing cliffs above a tributary of the Bivane River. The cliff tops are adorned in swathes of pink when the Gasterias are in flower during late September and October.

Haworthia limifolia.
Haworthia limifolia is one of many species that has declined seriously as a result of the medicinal plant trade in South Africa. There are many populations of this rare Haworthia inside the reserve. These plants are ideal for photography in the winter months up until about mid-November. The leaves take on a rich ochre hue and the thin raised ivory coloured striations which cover their surfaces become quite spectacular, during the dry warm months at the end of winter and into early spring.

Ledebouria zebrina.
One of the largest and densest populations of Ledebouria zebrina recorded from Natal is found within a few metres of the Bivane River below the dam wall. L. zebrina is the largest South African species and these plants have broad “zebra stripes” towards the leaf bases. In addition to the zebra stripes, which are spectacular in their own right, the inner leaf surfaces bear cloudings and blotching of purplish red brown bluish grey and underlying slate. The leaves are suffused with a powdery bluish bloom and look particularly attractive after winter grass fires. The spikes of numerous cream flowers and fresh leaves look at their best in late October and early November.

Pelargonium mutans.
P. mutans is a recently described shrubby species that occurs plentifully in the leaf litter below the cliffs at the northern end of the vast Gasteria batesiana colony. The strange white flowers of this unusual species are most readily seen in late winter and early spring which is the peak of the flowering period.

ACCOMMODATION AT THE BIVANE DAM.
Well appointed rustic thatched chalets have been built close to the waters of the dam. These are self catering and have spectacular views of the dam and surrounding mountains from the wooden decks of the chalets. There is also a caravan park closer to the dam with a full panorama of the surrounding countryside.

People wishing to visit the dam and the nature reserve should contact the Impala Water Users Association in Pongola 034 413-1314 or visit the web site www.bivanedam.co.za The reserve manager Mr. Dawie Cronje may also be contacted via email dc@bivanedam.co.za or by cell phone 083 321 9688.

FURTHER READING ABOUT CEROPEGIA CRAIBII.
Craib, Charles. An ecological account of Ceropegia craibii – a rare and beautiful species from Natal, South Africa.
American Cactus and Succulent Journal Vol. 74 No. 3 May – June 2002. 135 – 139.
Victor, Janine. Ceropegia craibii. Curtis’s Botanical Magazine, Volume 18, Part 4, November 2001: 210 – 213.

Ceropegia craibii tubers photographed about six months after the seeds’ germination. These seedlings were transplanted during the warm days of the early autumn.

A freshly opened Ceropegia craibii flower photographed adjacent to a well developed bud.