pandan (screwpine) leaves

here is a clip from this follwoing site. it has other pandan families as well if you are interested to look at them. but the first one (with a pic) was THE pandan leaves we use in cooking in SE asian cuisines.

http://www-ang.kfunigraz.ac.at/~katzer/engl/generic_frame.html?Pand_ama.html

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Pandanus (Pandanus amaryllifolius Roxb.)

Synonyms
bot Pandanus odorus, P. latifolius
Chinese Ban yan le
Danish Skruepalme
Dutch Schroefpalm, Pandan
English Umbrella tree, Screw pine, Screw tree
Estonian L hnav pandan
Finnish Kairapalmu
French Pandanus
German Schraubenbaum, Schraubenpalme
Hindi Ambemohor pat, Rampe
Hungarian Pandanusz lev l, Panpung lev l, Csavarp lma lev l
Indonesian Daun pandan
Italian Pandano
Khmer Taey
Laotian Tey Ban, Tey hom
Malay Pandan wangi
Norwegian Skrupalme
Portuguese Pandano
Singhalese Rampe
Spanish Pandan, Pandano
Swedish Skruvpalm
Tagalog Pandan, Pandan mabango
Thai Bai toey, Panae-wo-nging, Toey hom
Vietnamese Dua thom

Note
In European languages, there is no distinction between the single species yielding pandanus leaves and the group of species yielding pandanus flowers.

Used plant part
Leaves, always used fresh (slightly withered). Even in their native area, pandanus leaves are often replaced by an extract that also contains green food colouring.

Plant family
Pandanaceae (screw pine family).

Sensoric quality
The leaves's aroma is distinct and hard to describe, somewhat nutty, reminiscent to fresh hay and definitely pleasant. A similar scent is found in some aromatic rice varieties grown in South East Asia (e.g., Thai jasmine rice).
The scent of pandanus leaves develops only on withering; the fresh, intact plants hardly has any odour.

Main constituents
The flavour component of pandanus leaves is not well known. It is speculated that the flavour is due to a volatile product of oxidative degradation of a yellow carotenoid pigment that forms only when the plant whithers.
The best candidate is 2-acetyl-1-pyrroline, which was found in pandanus leaves (Cereal Chemistry, 70, 381, 1993) and which also occurs in aromatic rice cultivars; another possibility is ethyl formiate, which is also common to rice and pandanus leaves (Naturwissenschaften, 71, 215, 1984). The leaves also contain piperidine-type alkaloids (pandamarine, pandamerilactones) with pyrroline-derived structures (Phytochemistry, 34, 1159, 1993)

On distillation, the leaves do yiels traces of an essential oil, but it is unclear to which extent the volatile oil contributes to pandanus' flavour. In Sri Lankan pandanus leaves (Pandanus latifolius, allegedly synonym to P. amaryllifolius), the following aroma components have been identified in concentrations less than one microgramm per kilogramm (ppb) fresh material: styrene 0.62, ?formylthiphene 0.76, linalool 0.29, beta-caryophyllene 0.55, beta-farnesene 0.18, 1,2-dimethoxybenzene 0.15 and beta-selinene 1.24 ppb. (Phytochemistry, 21, 1653-1657, 1982)

Origin
Other than its flower yielding relatives (see pandanus flowers), P. amaryllifolius is not known in the wild state. Today, it is distributed over Southern India, peninsular South East Asia, Indonesia and Western New Guinea.
Male flowers are extremely rare, and there is no scientific description of a female flower for this species. It is also interesting to note that P. amaryllifolius is the only Pandanus species with fragrant leaves. Taken together, these signs, together with the lack of a wild population and the large distribution, imply a long tradition of cultivation. The only examples of flowers come from the Moluccas, and it is plausible that the species evolved there.

Etymology
The genus name derives from the Indonesian name of the tree, pandan.