Iguanura overview

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Only the keenest of palm collectors and growers are familiar with these delightful, small, pinnate palms from the humid jungles of Asia. The genus comprises some 18 described species found at low to middie elevations of south Thailand, Malaysia, Sumatra, and Borneo. There is usually only one species in a locality, often gregarious. One leaf-form usually predominates on a clump and is also most common in a single locality.

The generic name is derived from the resemblence of its flower stalk to the tail of the Iguana, an amphibian reptile. Iguanura species can be solitary or clustering sometimes reaching 3 metres in height. Very often Iguanura have just a rosette of leaves with two or three sinuous, slim trunks. The leaves are usually irregularly divided into broad, jagged tipped leaflets, and sometimes small stilt roots develop.

These little known palms are giving botanists a really hard time. The degree of leaf division is very variable which gives very different appearences to any given species. As well as this the inflorescence may branch variably. This has deceived many botanists into describing as different species, when in fact they are the same. The presence or absence of a crownshaft is another confusing feature. The flowers are unisexual, with the male flowers opening first.

In the Malaysian jungle the most commonly encountered are the following three species of Iguanura:

I. geonomaeformis

Fairly common in the lowland rainforest of the east coast. It can be solitary or can form small dense clumps, between 1 and 2.5 m in height, sometimes forming stilt roots. The leaves are 60 to 120cm long, greyish below, usually divided into broad irregular leaflets. Rarely the leaf is simple with a deeply forked tip. There is no crownshaft, the inflorescences are amongst the leaves, and rarely branched.

I. polymorpha

Mostly found in northern Malaysia, and also Sarawak. The stems are slender, with prominent joints. The leaves have a distinct crownshaft, with the leaflets rather distant, spreading like butterflies wings. The inflorescences are, below the crownshaft, and velvety, with a few spikes.

I. wallichiana

Distributed throughout Malaysia, Sumatra, and Borneo. Closely related to I. geonomaeformis except the inflorescence always has several widely diverging spikes. There is no crownshaft.

In his study of Malaysian Iguanura T.C. Whitmore describes the following forms, many of which appear to be a series of integrating forms of I. geonomaeformis, I. wallichiana, or I. polymorpha. I. arakudensis may be a form of I. polymorpha with short leaves.

I. bicornis

The leaves are with fishtail leaflets, a distinct crownshaft, and a peculiar seed broadening from a narrow base to a wide, two horned tip.

I. brevipes

Is different from I. polymorpha by the absence of a crownshaft.

I. corniculata

Is similar to I. polymorpha, but the fruits are horn like, strongly curved, and 2.5c m long.

I. spectabilis

This is the showiest of all the I. wallichiana group. The single stem grows to 2m with big entire leaves 120cm long that are bronzy pink when young.

I. fusa Another of the I. wallichiana extreme forms. The big leaves are finely divided.

I. parvula

A form with small entire leaves.

In Borneo the following species have been described. Other species are known, however descriptions appear scant.

I. elegans

A delightful little palm with an entire leaf, elongated.

I. melinauensis

I. palmuncula var. palrnuncula var. rnagna

Pinnate palms with peculiar, flat five crested seeds.

I. sanderiana

Another Iguanura with a reduplicate form of leaf.

For many years Iguanura had a reputation of being somewhat difficult to cultivate. Being essentially equatorial inhabitants of low to moderate altitudes, it is obvious that they require special care. Bottom heat for successful seed germination during the winter months would be an advantage in the sub-tropics. Young seedlings require light, a well drained medium, warmth, and plenty of moisture; basically the same treatment as Pinanga Even the youngest seedlings are very attractive with their round bifid primary leaves, slightly serrated edges, and a pink colour upon opening.

I obtained my first Iguanura in 1980 while still living in Sydney. The tiny, rather weak seedling travelled with me to Cairns where it strengthened and recovered rapidly. This was one of those very lucky acquisitions. The very small plant has grown into a beautiful, much admired, wide bifid leaved palm which is now the pride of my collection. After 8 years the plant itself is only 1. 2 to 1.5 m tall with three strong stems. New leaves are bronzy pink on opening measuring 30cm wide and 60cm long. The plant is just forming its first inflorescence, and I am hopeful that it will flower, and eventually set seeds.

During the last few years I have raised a number of Iguanura plants. The seeds lose their viability fairly quickly, however fresh seed will germinate within weeks. Seedlings grow fairly rapidly and should have three or four leaves within six months of germination.

In the wild, Iguanura keep their spent, dead leaves on the trunk for a long time, giving an untidy appearance. This is most likely the reason that they have been neglected by seed collectors for such a long time. However in cultivation, with a little care, they will grow into showy, compact plants which will be the crown jewels of every palm collection.

Contributed by:

Dusan Balint (from Palms & Cycads No 21, Oct-Dec 1988)

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