SUMMARY.
In recent times a number of new Ledebourias and Drimiopsis species have been found in remote mountainous parts of Mpumalanga and Limpopo Provinces. Many of these await formal description. One of them is a strange Ledebouria with beautiful leaves adapted to shady conditions in mountain woodland. This plant is currently only known from one locality on the Sandriviersberg at an altitude of about 1600 metres.

This newsletter concerns a discussion of the Ledebouria with specific reference to the unusual habitat it frequents in mountain top woodland on the summit of the Sandriviersberg.

NEWSLETTER.
The Sandriviersberg is a short range of mountains running from east to west with the highest peak Meletse at 1862 metres somewhat separate from the main range and inclined to the north east. The Sandriviersberg lies between the Waterberg and the Hoekberg. The Waterberg has the highest peak in the district, at an altitude of 2088 metres. To the immediate west of Meletse are the arid Vlieëberge, the highest peak lying at 1426 metres. All these mountains are under explored botanically except for the western end of the Waterberg which is fairly well known and lies within the Marakele National Park. Rainfall throughout this mountainous region and the surrounding arid savannah is in the summer from October until the end of March or early April. Prolonged droughts are frequent and during these times most of the bulbous and caudiciform flora remains dormant.

Meletse, the spectacular peak at the western end of the Sandriviersberg. The summit of the highest peak, hidden under a cloud, reaches 1862 metres whereas the lower peak lies at 1592 metres. The multiplicity of habitats on the southern and south western slopes of the mountain are clearly visible in this photograph. Botanically they are unexplored.

The mountain peak Meletse covered in a swathe of cloud. This photograph was taken in the afternoon on 25 February 2010 after a few days of soaking rain in the Sandriviersberg and surrounding area. The arid savannah at the foot of the mountain gives way to densely wooded gorges higher up. The summit peaks are largely grassland with a few trees.

THE DISCOVERY OF THE NEW LEDEBOURIA.
The new species was found by David Cumming, a resident of Bathurst in the Eastern Cape whilst on a field trip looking for Aloes. Specimens of the plant were subsequently grown by specialist horticulturalist Andrew Hankey at the Walter Sisulu Botanic Garden in Roodepoort near Johannesburg. Andrew maintains an extensive collection of Drimiopsis and Ledebouria, the most comprehensive in South Africa. Andrew is busy at present with studies on the new species and once further fieldwork is done in the Sandriviersberg in the summer of 2010 and early 2011 it is planned that he will have the plants illustrated and the type description drawn up.

The new species is superficially similar to another similar plant from the summit of the Blouberg in Limpopo Province. This plant is probably yet another new Ledebouria but there are certainly some differences in autecology and physical characters that require further study and delineation. The Ledebouria from the Sandriviersberg is clump forming whereas the species from the Blouberg is said to occur singly but also at high altitudes as found with the species growing in the Sandriviersberg. The Blouberg and the Sandriviersberg are remote and difficult to reach so it may be some years before adequate research on the two species on the different mountain ranges can be carried out.

The greater portion of the Sandriviersberg is well away from any access roads as is the Blouberg and it will require several days on foot to search the two mountain ranges thoroughly. A good starting point in the Sandriviersberg area would probably be Meletse as the two peaks on this mountain contain a large amount of varied habitat. The twin peaks on Meletse are at 1592 and 1862 metres and the southern and south eastern slopes below these peaks have numerous examples of extensive rocky shrubby mountain woodland. This seems to be the typical habitat occupied by the new Ledebouria.

The mountain on the farm Zandrivierspoort lies immediately south east of the Vlieëberge. The east-facing slopes are covered in dry mostly acacia woodland with open grassy patches. This habitat, adjacent to Meletse, would also be likely to reward exploration.

PRELIMINARY RESEARCH.
Some preliminary research on the new Ledebouria was carried out in early and late November 2009 in the eastern part of the Sandriviersberge. This was at the same place where David Cumming originally found the plants and also on damp mossy cliffs at the top of the mountain. Other areas that were searched were tall rock faces in excess of 30 metres and short rocky grassland on the summit of the mountain. This habitat is commonplace around seepage areas and seasonal watercourses which flow temporarily after good rainfall.

A cliff dwelling form of Drimiopsis burkei was found to be very common on exposed mossy cliffs in west-facing positions. These plants grew gregariously in places free from shrubs and grass in strong afternoon sunlight. When first examined in early November the Drimiopsis were in seed.

It was surprising to find on both field trips in November that the seepage areas on the top of the mountain did not contain any other Drimiopsis or Ledebouria species. Only a few square kilometres of habitat however were searched which hardly supplied a representative sample of the whole of the mountain top.

An extensive search was conducted for the new Ledebouria species. The habitat occupied by this plant seems to be unique in the genus. The bulbs occur in clumps and grow in sand and humus over huge sheets of rock, in shrubby deciduous woodland. This type of habitat is very dry for most of the year and requires abundant and regular rainfall in the early summer from late October
until early November for the bulbs to come into leaf. The rains begin in earnest in about mid-November but the Ledebourias had not emerged even at the end of that month when the habitat was very moist.

The leafing and flowering behaviour of this new species once again seems to be unique amongst Ledebourias frequenting the strictly summer rainfall parts of South Africa. The bulk of them grow in this region. Summer rainfall Ledebourias as well as many Drimiopsis species flower from early September until about mid-November depending on when the main summer rains commence in a given year. They flower and set seed before the main growth period of grasses and herbs.

The new Ledebouria is one of the very few, if not the only species, that has no competition in its habitat from grasses, herbs or even mosses and Salaginella. Further research is required but it seems likely that a minimum amount of moisture is required for the bulbs to break dormancy. Their arid well drained habitat is only sufficiently moist for flowering and leaf growth from about mid-December to late February. During dry years the Ledebourias are unlikely to leaf out at all.

FIELD VISIT IN LATE JANUARY 2010.
A field trip was planned to the locality in the Sandriviersberg on 28 January 2010 in the company of David Cumming. The good rains that fell in November had continued in December and January. The Ledebourias had come into leaf, flowered and shed their seeds during December and the first half of January, a period of only six weeks. As it was a good season for the plants some detailed observations could be made about their autecology and these are discussed below.

HABITAT NICHES OCCUPIED BY THE NEW SPECIES.
The south and south east-facing slopes of the Sandriviersberg have a varied composition of plants. The dense forests and the transition between these and mountain summit grassland, give way to dry woodland interspersed with shrubs and small trees. This is a vast area of tumbled boulders, sheets of exposed rock and gorges with seasonal streams.

Preliminary indications are that the Ledebourias are only found in very rocky places carrying a sparse woodland of trees and shrubs. The dominant deciduous shrub under which most groups of the Ledebourias were found was the Lavender Croton Croton gratissimus. They mostly grew in sand and humus over rocks, the soil in these places generally about six centimetres in depth. Other habitat niches consisted of soil filled cavities between boulders and broad fissures in vertical and sloping rocks filled with leaf mould and sand. The bulbs were nearly always found in groups and in suitable places, with patches of soil at least 60 centimetres wide, they occurred in dense clusters.

The niches occupied by the Ledebourias were always in light dappled shade. The plants avoid places with dense shade or exposed to direct sunlight. Also avoided were vertical rock faces and sparse patches of grassland in the more open areas. The bulbs have no competition from other plants in their habitat except for the occasional Croton which may take root in a rocky fissure. They were found to be well represented in a small area of only about 100 square metres. The remainder of the habitat was either too dry and exposed to strong sunlight or too heavily shaded.

Indications are that the species may be very rare overall even though numerous in a restricted part of the habitat. Further fieldwork needs to be done in the Sandriviersberge and surrounding mountains in order to determine the status of the species. It is hoped that this can be carried out before the plant is formally described.

CRYPTIC FOLIAGE.
Several species in the Genus Ledebouria have cryptic foliage and are easily overlooked as a result. This plant has leaves richly banded and marked with reddish brown and purplish black. In addition the shape of the foliage closely resembles that of fallen leaves in the habitat, particularly those of the Lavender Croton. The interplay of light and shadow in the habitat renders these Ledebourias even more cryptic in the places where they grow under shrubs.

LAND USE PRACTICES IN THE SANDRIVIERSBERG AND ADJACENT AREAS.
In recent decades the cattle ranches in the Sandriviersberg, particularly the lower western foothills around Meletse, have been converted to game reserves. The flora in the region is as a result well protected from habitat degradation. The new Ledebouria would be very vulnerable to habitat degradation particularly the introduction of goats into the area. These animals would quickly trample the bulbs in the thin sandy soil over rocks whilst they were browsing the surrounding shrubs.

Large indigenous herbivores such as kudu and rhinoceros, recently re-introduced to the area, graze in open savannah below the mountain and wooded grassland above it. Smaller antelope species and other herbivores have always lived in the Sandriviersberg and many bulbous plants such as these Ledebourias evolved with these grazers. An increase in the number of porcupines, which is so often associated with widespread crop production, is unlikely in the region. There is some irrigated crop farming near Sandrivierspoort south west of Meletse and also near the small settlement of Rankin’s Pass. This is however on too small a scale to increase the overall food supply available to porcupines. These large rodents are very destructive to some kinds of indigenous plants in crop producing areas where they have become numerous.

The new Ledebourias growing amongst leaf litter and tumbled boulders in their mountain top habitat on the Sandriviersberge. The typical occurrence of the plants is visible here in scattered groups with little competition from other plants.

The leaves of the Ledebouria match the shape of the dry foliage amongst the fresh leaf litter that surrounds them. This habitat the new species has, of growing in dappled shade in sand and humus, may prove to be unique for the Genus.

ACKNOWLEDGEMENTS.
I would like to thank David Cumming for his assistance in the field and for originally discovering this strange Ledebouria whose affinities are obscure.

I would also like to thank Andrew Hankey for his helpful discussions about this plant as well as maintaining it in the research collection at the Walter Sisulu Garden, for taxonomic studies.