Pinanga overview

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Pinanga, a generic name derived from the Berhasa Melayu (Malay) name for palms: 'pinang' (pi- as in pea, nang- as in young). Its current taxonomic position is in the subfamily ARECOIDEAE, tribe ARECEAE, subtribe ARECINAE. Its natural range occurs over the south-east Asian region from India, east to Taiwan, south into the Malay Peninsula, the Philippine Islands and Indonesian Archipelago to New Guinea.

With over 120 known species, and apparently many other awaiting study and problably description as new species, Pinanga is one of the largest palm genera, exceeded only by Calamus with about 370 species, Chamaedorea with 133 species, Bactris with 240 and followed by Daemonorops with 115 species and Licuala with about 110 species. Interestingly, Calamus, Daemonorops and Licuala have similar and overlapping ranges with Pinanga occupying similar environments. Pinanga is a genus almost entirely confined to the humid tropical rainforests, having no physiological mechanisms to withstand intense cold or dryness. A few species extend to cool montane forests or swampforests, but these environments still supply protection and constant moisture.

As a component of the vegetation, Pinanga is often abundant in the shrub-layer, sometimes even dominant, but there are very few species which attain tree-like stature, nearly all are shrubby and never reach into subcanopic heights within the forest. In adapting to life in the humid and dark rainforest, Pinanga has evolved several features which ultimately make them of interest to the palm collector. To catch as much light as possible, many species have moved away from the pinnate form of most Arecoid palm leaves, retaining pinnate venation but uniting the leaflets into broad segments, often of irregular location and size. Because of the reduced stature, many species cannot form large crowns capable of withstanding the damage often resulting from the constant rain of debris from above, so the ability to form basal shoots and thereby propagate vegetatively has been advantageous and has proliferated. This clump-forming habit means that the plants do not normally mature, senesc and die as single-stemmed palms do, rather the plant can eventually form a clonal colony, greatly extending its reproductive opportunities.

The dark conditions have also lead to the development of some very striking colours in the inflorescence and eventually the infructescence. It is not uncommon to have flowers of pure white, pink purple, red, maroon, orange or yellow, or various combinations of these. Presumably these colours serve to attract faunal pollinators. The fruits are variously coloured but often red or black In the latter case the infructescence branches are usually vividly pigmented with rich pink orange-pink or reddish colours. This is also presumably a means of attracting faunal seed-dispersal agents.

The ability to produce striking colours does not end with the flowers and fruiting structures, for the leaves, crownshafts, stems and roots can be coloured. Many species have coloured new leaves, often reddish, pinkish, brownish or yellowish, sometimes combinations of these, like the Philippine P. barnesii, which can be basically yellow with red, orange, pink and green suffusions. As the new leaf ages it gradually takes on the normal colour. Just why do these palms (and quite a few other genera besides) bother to colour the emerging leap There is probably no way to determine this, but a friend, who lived and worked in Malaysia for many years, and who was familiar with the forest ecology put forward an interesting theory. Dr B.C. Stone said that he thought the colours, which often made the new leaf look dry or dying, served as a deterrent to herbivorous predators which might otherwise eat the tender new leaf, causing severe problems to these small palms. This theory explains why herbivores such as mammals, which use sight to locate food may be deterred, but insects which often use scent would probably not fall for this trick.

The leaves are often attractively mottled with irregular patches of darker green. Sometimes the veins are suffused with colour, usually reddish, sometimes the leaf retains a rich surface mask of pigment, giving it a deep maroon appearance. Certain very desirable species have all these colour features, whilst a few are dull green. The crownshaft is often any colour but green. Yellow, brown, white, red, purple and even orange are tones variously suffused into this structure. The stems are often coloured, particularly in the larger, single-stemmed species like P. copelandii or P. speciosa, the latter having most remarkable black crownshafts and near black stems.

Pinanga even has the ability to colour its roots, or at least those parts which appear above ground, again the usual colours are shades of pink or red. The roots are mostly near the ground, even on old plants but a few species form definate stilt-roots and can layer their stems if they fall over, by forming roots anywhere along the stem.

P. polymorpha from the montane forests of the main range in Malaya has the ability to develop aerial roots and branches. Stems that fall over can form new clumps in this way.

One thing that is immediately apparent of Pinanga is that most species have curious soft, almost fleshy leaflets. Some are so soft that they seem unable to support their weight and have a texture more like cloth, P. bataanensis from the Philippines is such a palm. A few species have leaves which almost conform to the usual Arecoid palm fashion of being fully pinnate. P. scortechinii of Malaya and the similar although clump forming P. philippinensis from the Philippines have most of the leaflets separated, except for a small compound group at the leaf tip. Other species choose to have most or all of the leaflets united, often with each leaf showing different patterns in this way, P. geonomaeformis and P. disticha being obvious. The latter is a tiny Malaysian palm which also has attractively mottled leaves. The former, a small Philippine species has almost a metallic lamina with subtle pinkish colours.

Some species seem undecided as to the amount of separation within each leaf and vary enormously in this respect. P. limosa from Malaya can have some plants with undivided leaves, others with fully divided leaves and still others with both conditions on the same plant, with some leaves intermediate in form. The larger Sumatran P. kuhlii and P. coronata, which are closely related and very similar in appearance have fairly regularly divided leaves consisting of numerous groups of leaflets united together. The former tends to have broader segments and more colour, mottling and inflorescence colour than the latters. P. kuhlii is commonly cultivated in north Queensland and is one of the most attractive of the larger clumping species.

Just how big are these plants? The smallest, P. simplicifrons from Malaya and nearby Sumatra has tiny stems no greater than a chopstick in diameter and is usually less than 30cm high, whilst P. javana, the only species native to Java is a lofty tree like an Archontophoenix Most are intermediate of these extremes, ranging from 2 to 5 metres.

What are these plants like to grow?. As in any plant genus, there are some species which seem to be adaptable and others which require a very narrow range of conditions. Being essentially equatorial, sub-equatorial and low to moderate altitude palms of rainforest, it is obvious that Pinanga generally need warm and moist conditions. Some come from moderate altitudes and tolerate cooler temperatures. In Australia, growers from about Rockhampton northwards report success with an increasing range of species. South of the tropics the number diminishes and in temperate regions heat is required. Fortunately most species seem to be preadapted to our soils here and thrive in the ground if other conditions are suitable. Some nurseries have trouble with bulk lots of seedlings whilst others report success without any special treatment. My own experience indicates that any but the high altitude species seem to be easy to grow at any stage and often turn out to be far larger as adult than I had expected.

Some species seem to be very suseptible to damage from certain insecticides whilst being plagued with mealy bugs. It is safer to test a small section of leaf before spraying the entire plant. In regard to foliage colour and mottling, it appears that a certain degree of starvation actually enhances these features.

P. densiflora, probably the most handsome of the genus by virtue of its foliage colours, can become a deep, almost uniform green if heavily fed. In other species like P. kuhlii and P. coronata in which the leaves are mottled at emergence but fade to a more uniform green with age, heavy shading actually intensifies the mottle.

Many years ago, I saw my first Pinanga and was so impressed that I went to print, predicting an increase in interest in this genus amongst Australian growers. Certainly this situation has come about, there are now many species available and in north Queensland at least, it is hard to find a nursery that does not stock at least a few species. Hopefully collectors will continue to import new materials, increasing the cultivation potential of this charming genus.

Contributed by:

Robert Tucker from Palms & Cycads No. 16 July-Sept 1987

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