PENROCK SEEDS AND PLANTS NEWSLETTER: JULY AUGUST 2002.

Most habitats in which grass aloes are found have been altered or destroyed by widespread and extensive exotic afforestation. In many other areas habitats have been degraded by over grazing and taken over by informal settlements on the outskirts of towns. The grassland area around towns particularly in Mpumalanga and Natal housed some of the largest Grass Aloe colonies in South Africa. These have gradually disappeared under informal settlements. Grass aloes have evolved as part of a grassland fire ecology and many of those which flower between July and early December require fire to stimulate mass flowering. The smaller Grass Aloe species do not require the direct stimulation of fire in order to flower but do require the periodic burning of grassland to clear the habitat of moribund grasses. The flowering of these smaller species is often at its best the year after a major grass fire. The smaller grass aloes flower mostly in the late summer and early autumn from the end of January until the beginning of April, with a peak in February. Grass aloe seeds germinate erratically. This appears to be related to different moisture regimes within a given habitat and a tough seed coat that needs to be weathered by heat, light and water. This ensures that some seeds will germinate when climatic conditions are favourable. All grass aloe seeds are parasitised to some extent by insects, but the rate of parasitisation varies remarkably in a given population from one year to the next. Aloes are in general prolific seeders but this does not apply to the same extent with grass aloes, since many of them have only one raceme of flowers. There has also been the alarming trend where grass aloe populations between exotic forests in fire break grasslands set little or no seeds. This may be related to a lack of pollinating insects or sunbirds or even in breeding of the populations. Charles Craib and botanical artist Gillian Condy are currently working on a book on the ecology and cultivation of South African grass aloes. Most of the plants have been illustrated in habitat and there will be detailed observations on the ecology of these plants conducted over a 15 year period. This research was carried out at a time when grasslands have been undergoing one of their biggest transitions in the modern South African environment. If the predicted climate changes for South Africa take place grass aloes as a group will probably be exterminated. Those which inhabit mountainous areas may remain or adapt. Most grass aloes are readily grown from seed but some of them, particularly the smaller species, require specialised care in cultivation. A few of the rare dwarf species have already been tissue cultured and it looks as if they can be mass produced should this be warranted by horticultural requirements. CAPTIONS FOR THE THREE SLIDES. 6. ALOE HLANGAPIES. Aloe hlangapies is one of the larger grass aloes. It used to be well represented in the Piet Retief district of Mpumalanga but has largely been eliminated by exotic afforestation. It is now largely a plant of road reserves in this area. 7. ALOE CHORTOLIRIOIDES. Aloe chortolirioides is one of South Africa’s most unusual plants. It is found mostly in the Barberton area and is a species of mountain summit rocky grassland. The plants flower after grass fires and several years may pass without flowering if there are no fires. 8. ALOE MINIMA. Aloe minima is a species that inhabits cold frosty grasslands in Mpumalanga and Natal. It flowers in February. It has declined throughout its relatively wide distribution range and continues to decline. Aloe minima variety blyderivierensis is similar in most respects but usually has distichous leaves. It is now very rare and found only on a handful of hills near Graskop in Mpumalanga. Its habitat has largely been destroyed by afforestation with exotic pine plantations.