LEDEBOURIA OVATIFOLIA SUBSPECIES SCABRIDA, A SPECTACULAR BULBOUS PLANT FROM THE WEENEN DISTRICT OF KWA ZULU NATAL.

SUMMARY.
Ledebouria ovatifolia subspecies scabrida occurs mostly in short grassland on rocky hillsides in a small area of the Weenen district in Kwa Zulu Natal. The region where the plants are found is densely settled with rural villages and the habitat where the plants grow heavily grazed by livestock.

A preliminary survey was done of these plants in October and November 2009. This forms part of a study on land use patterns and habitat changes and the way in which these affect bulbous flora in South Africa. These details and the habitats frequented by the plants are discussed in the newsletter.

NEWSLETTER.
THE DISCOVERY AND DESCRIPTION OF THE LEDEBOURIAS.
L. ovatifolia subspecies scabrida was described recently in 2007 by two Natal botanists, Neil Crouch and Trevor Edwards (2007: 14 – 19). The same plants had been found previously by Stephanus Venter who published them under the name Ledebouria pustulata (Venter Herbertia 61 and 62 2007, 2008: 139 – 141). The authors of both names drew up their descriptions from different samples, one large colony of plants in the case of Crouch and Edwards and several populations in the instance of Venter’s description.

The two names given to the plants reflect the diagnostic leaf surfaces that characterise them. The numerous closely packed papillae give the leaves a scabrid appearance and the club shaped tips to these papillae resemble pustules. Both authors did not report in the samples, from which they drew up their descriptions, a pustulate leaved variant of Ledebouria ovatifolia. These plants are characterised by numerous rounded pustules that cover their upper leaf surfaces. During the study period one of these plants was found growing alongside typical L. ovatifolia subspecies scabrida and another in grassland about 6 kilometres away, but not associated with the subspecies. The same pustulate plants have also been found in rocky grassland at Twyfelfontein, north east of Mooi River, growing amongst typical L. ovatifolia. Their status remains an enigma and all that can be said at present is that they occur very sparingly together with L. ovatifolia and the subspecies scabrida as well as on their own.

HABITATS OCCUPIED BY LEDEBOURIAS IN THE WEENEN DISTRICT.
The area east of Weenen consists of arid Acacia thornveld with many rural villages. The countryside is heavily grazed by livestock, mostly cattle and goats. Ledebouria asperifolia has become very common in this overgrazed degraded habitat, but in contrast Ledebouria ovatifolia is rather scarce occurring on shaly hillsides in open places amongst shrubs and trees. The closest known occurrence of L. ovatifolia to L. ovatifolia subspecies scabrida is about 5 kilometres, as the crow flies.

L. ovatifolia subspecies scabrida was found to occur in more elevated rocky grassland than the other two species, usually at an altitude of 1200 – 1300 metres. The plants were found to occupy a distinctive habitat usually near the edges of mainly deciduous woodland. The most commonly frequented places were the summits of hills covered in dolerite boulders and smaller rocks and also the lower slopes.

In the colonies that were examined, most bulbs occurred in east and south-facing positions when they grew on hillsides. On hilltops or in more level rocky areas the bulbs received more hours of direct sunlight than they did on rocky slopes.

The plants grow in strong sunlight during the early leafing, flowering and fruiting period from mid-September until mid-November, particularly if there have been winter grass fires which clear the habitat of dry grasses and herbs. Later in the summer from the second half of February until the end of the growing period, late in March, the plants are provided with light shade by grass blades and annual herbs.

L. OVATIFOLIA SUBSPECIES SCABRIDA IN ITS CURRENT ENVIRONMENT.
The Ledebourias are unevenly distributed across their habitat and absent from several places that appear ideally suited to their requirements. All known colonies are very close to rural settlements but only a proportion of places suitable for the plants were surveyed in October and November 2009. It is not known at present if the plants grow on some of the high flat topped mountain peaks in the Weenen district, namely Umhlumba (1626 metres), Intuzuma (1624 metres) and Umkholombe (1524 metres). If the plants do occur on these mountain tops they would be well away from expanding rural settlements and grazing pressures associated with large and increasing numbers of livestock.

L. ovatifolia subspecies scabrida is usually thinly scattered across the countryside where it occurs. The numbers of plants are largely determined by the quality and variation of niches in a given habitat and the grazing pressures present in them. Plants on the rockiest hillsides fare best. Many of the plants here occur around rocks and in these places their leaves, flowers and developing fruit are protected from the hooves of grazing livestock.

The largest colony studied had several habitat niches consisting of steep and gentle rocky hillsides and more level rocky grassy areas above and below them. Good numbers of bulbs were also noted growing under Acacia trees where the grass cover is usually thin. An unusual artificial habitat consisted of grassy places around the edges of the stone walls of a disused cattle kraal (livestock enclosure).

Most livestock grazed on the summits of the hills where the grass was of better quality than that on the hill slopes. Regeneration of bulbs was evident with seedlings and young plants present in small numbers over most of the habitat.

The Ledebourias were scarce at two other localities. One consisted of a low rocky outcrop in otherwise heavily grazed grassland. This place was frequently trampled by cattle and goats walking across the outcrop on their way to grazing. The small colony consisted of about 40 mature bulbs, mostly with shredded trampled leaves and no evidence of regeneration.

The other locality consisted of a large boulder strewn hill with a flat summit containing open grassy areas interspersed with rock outcrops. The hilltop was heavily grazed by cattle, donkeys and goats and the Ledebourias almost entirely confined to soil pockets amongst rocks. The few plants that there were in the open grassy areas had their leaves and inflorescences thoroughly trampled by livestock. A small number of seedlings were observed, all of them in soil pockets amongst rocks.

THE GROWTH CYCLE.
L. ovatifolia subspecies scabrida grows, flowers and sets seed during the spring and early summer from mid-September until early December. The leaves are developed fully by December and remain green throughout the summer until the autumn, about early April, when cooler dry weather begins. The flowering period, usually from late September to mid-October, coincides with hot dry spring weather. If rains begin early the plants may receive some rainfall in the first half
of October but early to mid-November is usually the time when the summer thunderstorms begin.

Seeds are set in October and the quantity produced varies greatly from one season to the next. Ripening seeds are often trampled by livestock in heavily grazed areas with the result that there is very little regeneration from seed in these places. In addition, developing seeds are often eaten by lepidopterous larvae, compounding the problem. If the spring is rainless with high temperatures most plants that have flowered fail to produce any seeds at all.

Seeds germinate in November with the onset of the main summer rains. Germination is usually rapid, occurring within 7 – 10 days, but many seedlings shrivel in the sun if there are long intervals between rain. The young plants develop best in places that retain moisture for longest after rainfall and also in rocky areas protected from the hooves of grazing livestock.

Seedlings develop throughout the summer and establish themselves quickly. In cultivation young plants often produce 3 – 4 leaves up to 2 cms long within 8 weeks after germination.

The grassland in which the subspecies grows is frequently burnt during the winter months to promote spring and early summer grazing for livestock. These conditions are ideal for the plants as they clear the veld from moribund grass. They would be much better represented were it not for the fact the newly emerging grasses are heavily grazed and the plants, their flowers and seeds trampled as a result.

SURVIVAL IN THE FUTURE.
One of the biggest problems facing South African plants this century is habitat destruction and degradation, nearly all of it associated with ever increasing numbers of people. The present known distribution of L. ovatifolia subspecies scabrida is only about 15 square kilometres in extent and this area is characterised by all of the problems associated with rises in the number of people in rural settlements and their livestock. At present it is not known if the plants occur elsewhere. If so, their future may be more secure.

The data collected so far shows that the subspecies is likely to be declining mainly through little if any regeneration from seed. It is also noteworthy that plants with broad flat leaves and inflorescences borne at, or just above, ground level decline sharply in heavily grazed areas. It seems apparent that the numbers of these Ledebourias will decline but variation in grazing patterns also needs to be taken into account. A good example is the locality where the plants are presently well represented, but where the disused stone kraal indicates that livestock was once present at the site.

CULTIVATION.
The Ledebourias are easily cultivated in deep broad pots that can accommodate the relatively large bulbs. These should be planted about 8 – 10 cms apart with the top of the bulb buried just below the surface. The wide spaces between the bulbs allows them to develop their broad ornamental foliage to its fullest. The plants thrive best in a well drained gravely mixture, a suitable medium being a third loam, a third river sand and a third very well rotted finely sieved compost. The pots should be placed in strong direct sunlight or very light dappled shade and the bulbs regularly watered throughout the spring and summer months. They should be kept dry during the winter from the time the leaves start to die back until they emerge once more the following spring. At this time watering should be resumed.

The rich mauvish or purplish red brown colour that characterises the papillae on the leaves is at its best under conditions of strong light. Under shaded conditions the papillae remain ivory coloured or a dull Naples yellow.

The subspecies is readily grown from seeds. These should be lightly scattered across the surface of the germination mixture and just covered. Seeds normally germinate within about 7 – 14 days after they have been sown and watered.

Very good results are obtained if the pots in which the seeds have been sown are kept out in the rain. In common with most indigenous plants rainfall enhances germination and development of the seedlings. Heavy raindrops can be broken by placing a covering of aluminium fly screen netting over the top of the pot and securing it around the rim with a piece of string or garden wire. The screening can be removed once the seedlings have developed their first two leaves as by this time the young plants are able to resist being washed out of their containers by strong rainfall.

The seedlings should be kept dry from the time the leaves show signs of withering until the following spring when watering can be started once again. The young bulbs are ready to be separated and planted out into large deep containers at the end of the winter following their first growing season. In South Africa, as probably elsewhere in the Southern Hemisphere, this is best done during the first half of August.

REFERENCES.
N.R. Crouch, T.J. Edwards and Angela Beaumont. Ledebouria ovatifolia subspecies scabrida. Flowering Plants of Africa, Volume 60, June 2007: 14 – 19.
S. Venter. Synopsis of the Genus Ledebouria Roth (Hyacinthaceae) in South Africa, Herbertia, Volume 61 and 62, 2007, 2008: 139 – 141.