Pandanus species of the Wet Tropics of Queensland, Australia 1. P. brookei (Martelli) 2. P. cookii (Martelli) 3. P. dammannii (Warb.) 4. P. gemmifer (St. John) 5. P. lauterbachii (Schum. & Warb.) 6. P. monticola (Muell.) 7. P. solms-laubachii (Muell.) 8. P. tectorius (Parkinson) Pandanus brookei - no info Pandanus cookii Photo supplied by John Beasley, taken above Davies Creek Falls. JB says "There are short prop roots at the base, not visible in the photo, and the fruit (Nov-Mar) are orange-red, a bit like gemmifer." Pandanus dammannii synonyms : P. arnhemensis (St. John), P. medialinermis (St. John), P. orbicularis (St. John), P. stolonifer (St. John) Pandanus gemmifer from "Flora of Australia" by CSIRO : Grows in highland rainforest on the edge of lakes and streams. The tree produces plantlets (bulbils) on the trunk which fall to the ground and take root, forming thickets. The spiral direction of the leaves becomes reversed after each flowering. Pandanus lauterbachii I am not sure where this photo came from now, possibly a botanical garden in California. According to "Flora of Australia" by CSIRO, P. lauterbachii does not have prop roots, so something is wrong here. Pandanus monticola synonym : P. pluvisilvaticus (St. John) Pandanus monticola is restricted to the reduced light conditions of the rainforest. P. monticola has shorter, narrower leaves than P. solms-laubachii, that are arranged on their stem over the top metre or so, pointing upwards at 45° to start off with. The stems are narrow, about 3 cm diameter, and are unable to keep the plant upright, so they sprawl in a tangle with vines and each other. When the barbed leaves from two stems interlock, they form an impenetrable barrier. They have male and female flowers on different plants (dioecious). The male inflorescence, below, is about 60 cm long, with large white bracts that have an unusual "off" scent that attracts flies. The female flowers have a stem about 10 cm long. The female flower is well-protected within the enfolded thorny leaves and the early fruit swells quickly, until the stalk lengthens and the mature fruit hangs free. This is a close-up of the male "catkin" showing the individual stamens. The fruits are large and prickly and are a favourite of the Sulphur-crested Cockatoo, that rips off a chunk and then scatters most of the pieces across the forest floor. Pandanus solms-laubachii synonyms (all St. John) : P. citraceus, P. kurandensis, P. mossmanicus, P. papillosus, P. punctatus, P. radicifer, P. rivularis Notice how the leaves seem to radiate out from the growing apex in a hemisphere, and how thick the trunk is immediately below the apex. Where the old leaves have fallen away, the exposed trunk shows leaf scars and is otherwise smooth and shiney. But further down the bark becomes dimpled and then it develops "prongs" which are brittle, woody spikes up to 7 cm long, with some hooked thorns that grow vertically close to the bark. This surface is a good place for spiders' webs and trapped leaves, debris, moss, epiphytes and lichens. (Lichens are the combination of an alga embedded in a fungus. This association is mutually beneficial - the alga gains protection from drying out, and the fungus absorbs some of the sugars the alga produces by photosynthesis.) The base of the trunk is supported by prop roots, but in this species they are not well-developed. Sometimes these trees grow to 10 metres without branching, but it is much more common that they divide into two or three branches, that may themselves divide again. The angles that the branches make have an primitive "un-natural" look about them. The species is dioecious, meaning each plant is either male or female. This is a female inflorescence, or compound flower, which will develop into the fruit. The three leaves surrounding the flower are lacking chlorophyll in their lower halves. The bracts that surround the flowers are white and release an 'off' smell that attracts flies, presumably they bring pollen from a nearby males to fertilise the flower. The developing fruit has a pineapple shape, but at maturation the core swells up and the shape becomes round as the segments pop-off. The central core has a texture like wet paper maché. When the segments have fallen away, the stalk and core of the fruit hangs from the stem for many months. When the fruit is freshly fallen, the base of the fruit segment has some firm, fibrous flesh that can be sliced away and eaten. It has an aromatic smell and a peppery taste that is best swallowed quickly. I cannot guarantee that you won't get a stomach upset from this. After a few hours sweating under a summer sun, the fruits start to ferment and the smell attracts butterflies and bees. Within a couple of days, all the flesh has been removed, leaving a stump of stiff fibres. The fruits are compound with about 100 segments (phalanges) forming one pineapple-like fruiting body, with each segment having 7 to 15 chambers. Each chamber is a narrow tube in the central woody core, where the seed forms, and a hollow woody extension which acts as a bouyancy support. In about half of the segments that I have opened, there are 1 or 2 chambers with an oily seed in them. The longest leaves come from the unbranched trees. I measured this leaf to be 4.13 metres and its fine tip was already broken off. The leaf has parallel veins with thorns mounted on the two leaf edges and also on the underneath side of the mid-rib in the upper half. The leaf section is deeply channelled, giving the leaf stiffness. But when it collapses, it usually stays collapsed, giving the typical 'Pandanus' look. Two long, flat strips can be easily cut from the edges of the leaf with a sharp blade. The thorns on the margin can also easily be cut away, leaving strips that can be dried and woven or used as string. Thorns are much heavier on the margins near the base, where they are well-placed to catch falling debris. I do not know how this could help the plant. The leaves clasp the stem and are set somewhat over 120° apart, giving the arrangement of three leaves that form 3 spirals. This gives the species its common name of "Screw Pine", although this is a flowering plant, not a true pine. The fruit is large and quite heavy, so it needs a strong stalk to hold and feed it. When the old stalk falls away it leaves a socket, and two buds (?) sometimes form there. These sockets are approximately 140 mm apart, and perhaps represent a year's growth. Notice the leaf scars. At the middle of each scar there is a triangular feature that is presumably an axial bud , and these develop in size as the branch matures, forming three spirals up the branch. At each fruiting point, the handedness of the spirals reverses itself, as also noted for P. gemmifer. Branched trees can have different handed spirals simultaneously. Pandanus tectorius synonym : P. pedunculatus The kernels taste OK, and are said to be very nutritious, but they weigh only about 0.1 gm each. Unknown Pandanus sp. This unidentified species is similar to P. solms-laubachii, but the leaves are not crowded at the end of the trunk, and they show a distinct spiral arrangement that forms a triple helix around the trunk. Since the plants are dioecious, it is possible there is sexual dimorphism. Could this be just the male of the species ? The thorns are much heavier and set more aggressively than P. solms-laubachii. The leaf on the underneath side of the mid-rib carries thorns in its lower half, and these point back towards the base. In the upper part, the mid-rib has thorns point towards the tip as in P. solms-laubachii. The arrangement of thorns makes the plant particularly good at catching debris. P. solms-laubachii (left) has prop roots crowded around the base, while this species (right) has prop roots in an open formation reaching 900mm up the trunk. Sometimes the main trunk is only very thin at the base. The bark does not have 'prongs' like P. solms-laubachii, but has lenticels(?) like P. tectorius . This 10m tall specimen was snapped off during Cyclone Larry. Dave Kimble January 2006 You can support my not-for-profit causes by making a donation by secure on-line transaction. Thank you.