This being the 50th episode of this series on wildflower conservation, it’s appropriate to devote it to the most beautiful, well-known and best loved of plant families – Proteaceae, the proteas. Everyone is familiar with the South African national flower, the king protea Protea cynaroides. What is perhaps less well-known is that it belongs to a very large family of related plants with a worldwide distribution. I hope this brief introduction stimulates farmers and landowners in areas where these fascinating plants occur to get to know them better.
Confined to the southern hemisphere, Proteaceae is an ancient family that existed well before the break up of the super-continent Gondwanaland some 140 million years ago. The occurrence of members of the protea family on continents as far apart as America and Australia provides evidence of continental drift. T here are about 60 genera with 1 400 species world-wide. Australia has the most species, over 800, representing 45 genera.
In South Africa Proteaceae are grouped into 14 genera including the familiar proteas and less familiar ones such as pincushions (Leucospermum), conebushes (Leucadendron) of which the silver tree is the most familiar, spiderbushes (Serruria) epitomised by that lovely flower the blushing bride, and a number of less familiar genera. Of the 360 South African species, at least 330 are confined to the Cape Floral Kingdom, extending from Nieuwoudtville in the northwest to Grahamstown in the east, with a concentration of no fewer than 130 species in the Caledon district.
In the southwestern Cape they are largely confined to nutrient-poor soils derived from Table Mountain sandstone, but a few occur on the limestone soils of the Agulhas plain and a very few on shale-derived clay soils. While an important element of Cape Fynbos, most protea don’t have the small fine leaves of most Fynbos plants, but have hard, leathery leaves, a quality that prevents water loss during dry summers.
Dangerously limited habitat
Some species are confined to specific mountain ranges in the Western Cape and some are limited to isolated local populations in obscure places. he marsh rose Orothamnus zeyheri, for instance, is known only from a few isolated populations in peaty areas and seeps in the Kogelberg and Kleinmond mountains. Some species have only recently been discovered and there may well be species yet to be found. More than 125 species are listed in the Red Data Book as rare plants threatened or vulnerable due to loss and destruction of habitat, and for which urgent conservation strategies are necessary.
There are well-documented cases of at least four species that have become extinct in recent years. Proteaceae are found in a great variety of shapes and sizes, varying from small shrubs to tall trees, with the common characteristic that they are all woody plants. Some protea have underground stems from which shoots and flowers emerge, and are commonly referred to as ground proteas. Many are resprouters after fire, but others are killed by fire and rely on regeneration from copious amounts of seed released from seed heads that only burst open after the plants die. Proteas that depend entirely on seed production for recruitment are very vulnerable to frequent fire. Since it may take up to 10 years for plants of some species to mature and produce seed, large populations have been wiped out by fire occurring at shorter intervals.
The flowers are adapted to a variety of pollination strategies including insect and wind pollination, and rodents in the case of ground proteas. Sunbirds and sugarbirds are attracted by the sweet nectar. In fact the name sugarbush is derived from this feature and syrup is harvested from a common and widespread species, Protea repens. Some members of the Proteaceae family such as conebushes and featherbushes (Aulax) are dioecious (male flowers on one plant and female another). A number of striking species occur in the summer rainfall region from the Eastern Cape through the Drakensberg and into central Africa.
Having lived nearly all my life in the Eastern Cape I first came across proteas in the Amathola mountains where three species occur. There are even some pincushions and conebushes in the summer rainfall region. In the early 1990s I participated in the nationwide Protea Atlas Project recording wild species populations. I tracked down summer rainfall species. This exciting project took me through the northeastern Cape, east Griqualand, KwaZulu-Natal, Swaziland and Mpumalanga. I was even able to find and record Protea curvata, a small tree species confined to a single farm near Barberton.
The project resulted in an excellent illustrated field guide titled Sasol Proteas, produced by project leader Tony Rebelo and published by Fernwood Press.
Profitable protection Protea flowers and foliage are harvested on a sustainable basis from wild populations in the Cape mountains.
The commercial cultivation for the cut and dried flower trade is now a multibillion-dollar international industry, earning foreign capital and providing income and employment for thousands of people in the Western Cape. Our proteas are well adapted to regions with a Mediterranean climate such as California, Australia and New Zealand. Contact Cameron McMaster at [email protected] |fw