Palms have the largest leaves of all trees, and Raphia
has the largest leaves of all palms. One species of these monsters
is indigenous to South Africa, and that is the majestic Kosi palm.
Tree, often up to 16 m tall, rarely stemless, usually solitary,
monoecious (separate male and female flowers on the same tree),
monocarpic (flowers once and dies). Leaves pinnate, often very large;
petiole unarmed; rhachis with small ascending spines, leaflets reduplicate
(central fold up, like an upside-down V), linear, 450-?650 x 50
mm, margin and midrib spiny. The inflorescence (flower spike) is
covered by an enormous sheath up to 3m long, which falls away allowing
the inflorescence to continue skywards (resembles a floral rocket
launch!) Peduncle (flower stalk) covered by 2-ranked, imbricate,
gaping bracts; branches and abbreviated flowering branchlets laterally
compressed, laxly arranged or congested in one plane; bracts 2-ranked,
imbricate. Flowers 2-ranked, female near base; males on upper part
of spadix. Male flower with a 2-keeled bracteole; calyx tubular
or 3-lobed; petals 3, free or nearly so; stamens 6 to many, free
or joined. Female flower with an outer and an inner bracteole and
a joined calyx and corolla; staminodial ring joined to corolla;
anthers minute or not present; ovary 3-locular, with 1 ovule developing;
style short with 3 stigmas or not present. Fruit 1-seeded, ovoid,
60-?90 x 30-?50 mm, covered with brown, imbricate scales arranged
in vertical rows, each with a median groove; apex beaked.
Distribution and Habitat
The natural distribution of the Kosi palm is restricted to a small
area stretching from just south of Kosi Bay to 40 km or further
north of Maputo. The population at Mtunzini is descended from cultivated
trees. These trees are found on seasonally inundated dunes, and
have pneumatophores (breathing roots) like mangroves.
Derivation of name and historical aspects
Jackson (1990) gives two derivations which are equally plausible:
- the Malagasy word for the fibre derived from the leaves of
R. ruffia is rafia, or in English raffia, which
could give rise to the generic name
- the name could be derived from the Greek rafis, a needle,
referring to the pointed frond. Smith & Stearn (1972) do not
mention the first explanation, but say the second refers to the
beaked fruit. The specific epithet australis, meaning southern,
is highly appropriate to the Kosi palm, southernmost representative
of this genus.
The species epiphet australis means southern, not Australian,
which is australiensis.
It was only in 1968 that a Kosi palm tree in the Natal Herbarium
garden in Durban was seen flowering, and it was realised that this
was, in fact, a new species. Until that time it had been thought
that the Mtunzini and Kosi Bay trees were the southernmost populations
of Raphia vinifera Beauv., a West African species.
There are about 20 species of Raphia, mainly from tropical
Africa and Madagascar; one comes from South America, and one is
found in southern Africa, straddling the border between KwaZulu-Natal
The raffia fibre used by gardeners is derived from R. farinifera
(Gaertn.) Hyland., a species from tropical Africa and Madagascar,
which differs most strikingly from our species in that it suckers.
There are also several subtle floral differences separating R.
australis from R. farinifera and the West African R.
vinifera. A West African raphia holds the record for the largest
leaf ever measured, with a rachis over 25 m long.
The fruits are an important item in the food supply of the palm-nut
vulture. The channelled rachis directs water into the leaf axils,
which quickly fill with humus and so become ideal habitats for various
epiphytes, mostly ferns and fern allies. Like palms of the genus
Caryota (fishtail palms), the Kosi palm flowers once at an
age of between 20 and 40 years, and then dies. The seasons do not
seem to be of major importance in initiating flowering, but the
trigger is unknown. Fruits remain on the tree generally until blown
down by high winds, which may only happen a year or two after they
are ripe. It seems that in nature, they are mainly dispersed by
Uses and cultural aspects
The palms at Mtunzini station are a declared National Monument,
and at least part of the Kosi population is within a nature reserve.
Few uses are recorded for this rather rare palm. The raffia fibre
of commerce, much used in horticulture, is derived from R. farinifera,
although most raffia sold in garden centres today seems to be a
plastic imitation. Coates Palgrave (2002) notes that the vast petioles
and midribs of the Kosi palm are used in Mozambique to make outriggers
for canoes, as they float. WESSA attempted to use them to make footbridges
over drainage ditches at Twinstreams, Mtunzini, but found that although
they were strong enough to support single pedestrians, they neither
supported the groups of enthusiastic teenagers who erected them
nor lasted in the soil. However, the pictures accompanying the first
scientific description show not only a raft made of Kosi palm, but
market stalls and a bus shelter constructed of this material. Obermeyer
& Strey (1969) report that unlike some West African species
of Raphia, the Kosi palm is not tapped for wine-making. According
to Coates Palgrave, craftsmen have converted the midribs and rachises
of raffia palm leaves into boutique furniture, which should be possible
with the Kosi palm, too. Fruiting spikes of Kosi palm make good,
if bulky, 'African' ornaments. Kosi palm trees are rarely seen in
gardens, and then only in large ones in warm areas.
Growing Raphia australis
These palms are dramatic accents in parks and large gardens, but
are not suitable for containers or confined areas, as they are far
too large for small gardens. Their natural habitat range suggests
that they are frost sensitive, but some are to be seen in relatively
cold situations around Kloof, Gillitts and Hillcrest in the Durban
area. A witty comment in a horticultural description of a fishtail
palm suggested that the latter make ideal street trees as they grow,
flower and die within twenty years, which is about the usual length
of time between renovations of the street layout. Much the same
could be said of the Kosi palm, if it is given sufficient water,
for the same reason. However it would probably be a bad choice for
a shopping mall, as there the roads seem to be re-aligned much more
often than every 20 years, and sufficient water would be a problem.
Fresh seed grows easily once the outer scales have been removed.
Seedlings need filtered sunlight, plentiful water and protection
from wind. Very little, if anything, else is known about the cultivation
of these palms. In particular, I have yet to see one attacked by
a pest or disease. However, untreated fruits used for ornament may
eventually be subject to attack by cigarette beetles and other similar
insects. The usual treatments (freezing, fumigation, insecticide
spray) are adequate to control this provided that the damage is
noticed in time.
References and further reading
- Coates Palgrave, M. 2002. Keith Coates Palgrave Trees of
southern Africa, edn 3. Struik, Cape Town.
- Jackson, W.P.U. 1990. Origins and meanings of names of South
African plant genera. Botanical Society of South Africa, Cape
- Obermeyer, A.A. & Strey, R.G. 1969. A new species of Raphia
from northern Zululand and southern Mozambique. Bothalia 10:
- Otedoh, M. 1982. A revision of the genus Raphia Beauv. (Palmae).
Journal of the Nigerian Institute of Oil Palm Research 6,22:
- Smith, A.W. & Stearn, W.T. 1972. A gardener's dictionary
of plant names. Cassell, London.
- Wicht, H. 1969. The indigenous palms of southern Africa.
Timmins, Cape Town.