Difference between revisions of "Raphia australis"

Revision as of 23:23, 16 July 2014

Raphia (rahf-EE-ah) australis (aw-STRAHL-iss)
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Scientific Classification
Genus: Raphia (rahf-EE-ah) Species: australis (aw-STRAHL-iss)
Synonyms
None set.
Native Continent
Africa
Morphology
Habit: Solitary Leaf type: Pinnate
Culture
Survivability index
Common names
Kosi Palm, Kosi Bay Giant Raffia Palm, Kosi palm (Eng. & Afr.); umVuma (Zulu); iMali (Ronga).

Habitat and Distribution

South Africa. Cape Provinces, KwaZulu-Natal, and Mozambique. 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. (plantzafrica.com H.F. Glen Natal Herbarium) [[

Description

Tree, often up to 16 m tall, rarely stemless, usually solitary, this genus is monoecious, also monocarpic. 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. (plantzafrica.com H.F. Glen Natal Herbarium) Editing by edric.

Culture

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. (plantzafrica.com)

Likes full sun, and bad drainage. Given these conditions, they are very fast growing, one of the fastest of all palms. If you don't have a swamp, then give them lots of water. Needs at least a sub-tropical climate. Cold Hardiness Zone: 10b

Comments and Curiosities

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. (plantzafrica.com H.F. Glen Natal Herbarium)

Derivation of name and historical aspects (Etymology) 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. (plantzafrica.com H.F. Glen Natal Herbarium)

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. (plantzafrica.com H.F. Glen Natal Herbarium)

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 and Mozambique. (plantzafrica.com H.F. Glen Natal Herbarium)

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. (plantzafrica.com H.F. Glen Natal Herbarium)

Ecology: 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 palm-nut vultures. (plantzafrica.com H.F. Glen Natal Herbarium)

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. (plantzafrica.com H.F. Glen Natal Herbarium)

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. (plantzafrica.com H.F. Glen Natal Herbarium)

They provide the home, and food for the palm nut vulture, (the worlds only vegetarian vulture (not quite, they sometimes snack on the occasional small animal)), which feeds on this palm's fruit, and that of Elaeis guineensis .

"The beatiful giant grows all over the southern half of Africa. They love water, and always saw them in boggy conditions. They were growing in Kirstenbosch in Cape Town South Africa where they do get frost, and long cold wet winters, cooler than most parts of Southern California. I haven't tried one yet, but am thinking of giving one a go in Northern California." (Kyle Wicomb)

"Solitary stemmed Raphia palm from S Africa where it grows in swampy soils. The leaves can grow up to 60' long (longest leaves of the plant kingdom), but only seem to in really tropical, boggy situations. Used for raphia to weave baskets and make twine. Also has edible pith for flour. This majestic palm has been successfully grown in southern California in some nearly frostless situations, though none have formed trunk yet that I'm aware of. Seem to do OK.. nice orange color in petioles when young (similar to Raphia farinifera)." (Geoff Stein)

External Links

• Glossary of Palm Terms
• MODERN BOTANICAL LATIN
• "Just To Be Clear"
• http://www.kosimoon.co.za/kosi-bay-news/kosi-bay-giant-raffia-palm-or-raphia-australis/
• http://www.pacsoa.org.au/palms/Raphia/australisM.html
• http://www.dwaf.gov.za/events/ArborWeek/2006/trees.asp

References

Phonetic spelling of Latin names by edric.

Special thanks to Geoff Stein, (Palmbob) for his hundreds of photos.

Special thanks to Palmweb.org, Dr. John Dransfield, Dr. Bill Baker & team, for their volumes of information and photos.

Glossary of Palm Terms; Based on the glossary in Dransfield, J., N.W. Uhl, C.B. Asmussen-Lange, W.J. Baker, M.M. Harley & C.E. Lewis. 2008. Genera Palmarum - Evolution and Classification of the Palms. Royal Botanic Gardens, Kew. All images copyright of the artists and photographers (see images for credits).

Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.