Rattan palms are from tropical and subtropical areas of the world especialy S.E. Asia.
The largest palm genus it has 416 species with 57 from New Guinea and 2 in Queensland.
Australia has 8 species with one, Calamus muelleri the Southern Lawyer vine in S.E. Queensland.
Most are solitary single-stemmed climbing palms with stems that can be over 60 m long.
Stem thickness ranges from a few mms to over 15 cm.
Some are multi-stemmed and sucker to form spreading clumps.
A few are shrubby or have no stem.
Stems of young climbing palms have spines but these are lost on older palms.
Leaves, up to 2 or 3 m long are almost always pinnate and with or without a petiole.
Petioles are flattened on the upper surface, rounded on the lower and have curved spines.
The tubular leaf sheaths fit tightly around the stem.
The exposed parts can be smooth, hairy or have scattered to dense dark spines up to 1 cm long.
The top of the sheath may have a long or short extension – an ocrea.
The straight or curved midrib (rachis) typically has downward curved thorns (sharp woody modified stems).
Along the midrib are a few to 100 or more leaflets either singly or in small groups.
Leaflets can be arranged at regular or irregular intervals.
They can be horizontal or pendulous and those in small groups can be in one or more planes.
Leaflets, up to around 1 m long have a narrow base and a wide flat or oblique tip (praemorse).
The 2 terminal leaflets are joined at the base.
Leaflets can be dark to bright green on both surfaces or the lower may be paler or silvery.
Hairs, scales, bristles or spines are commonly present on the edge and lower surface of the leaves.
Some palms have a long thin barbed flagellum that develops from an inflorescence.
Palms without flagellae may have a similar barbed whip (cirrus) growig from the end of the leaf midrib.
Inflorescences are axillary but the peduncle is attached to the stem above the base of the leaf/petiole.
The erect or pendulous inflorescences have a prophyll that is usually small and tubular with 2 keels and spines are common.
There are peduncular bracts at the base of the short side branches (partial inflorescences).
All bracts may or may not have spines.
Male and female inflorescences are on separate palms.
Male inflorescences, usually branched 3 times have solitary flowers.
Female inflorescences, usually branched to 2 orders have flowers in pairs of a female and a sterile male.
Pale yellowish flowers, usually with no stalk have a bract under them.
Male inflorescences have flowers with 3 sepals and 3 usually longer petals both with a tubular base.
The 6 fertile stamens are attached to the top of the corolla tube.
Anthers open inwards or sideways and there is a tiny or no pistillode.
The sterile male beside each female flower has similar anthers but with no pollen.
Female flowers are roughly similar but usually have slightly larger sepals and petals.
The ovary, of 3 carpels has vertical rows of scales and is topped with 3 stigmas.
Each of the 3 locules has 1 ovule but usually only one develops.
There are 6 staminodes with empty anthers.
The fruit, typically roughly spherical and covered in scales are up to around 3.5 cm across.
The white, red or yellow fruit have a very thin fleshy layer around the seed.
The round seed may be grooved, angled or winged.
(The terms prickles, spines and thorns all have specific meanings.
Distinctions depend on what structure they develop from and if they are vascularised or not.
However the terms are often loosely used.
Nonspecific terms such as ‘barb’ and ‘armed’ are often used to cover any or all of them.)
J.F.
