These are almost exclusively South-East Asian instruments – ‘almost’ because we have one example from Lapland. They may well exist or have existed also in other places, but so far we have no evidence for them.
The reed consists of one or more short vertical (ie parallel with the length of the stalk) slits in the upper end of a stalk of a fairly soft material such as a rice stalk that is closed at the top by a node. They seem always to be wholly idioglot. Cutting fingerholes in such material is not easy but it can done with a very sharp narrow blade; an easier method is with the burning end of a cigarette or a hot iron. They are ephemeral, lasting only a short time. The only examples that I have seen in museums have been preserved in tubes full of alcohol or other preservative liquids, since otherwise they would simply dry up and disintegrate.
They are called dilating reeds, or retreating reeds, because when the slit end is held in the mouth and blown, the slit rapidly opens and closes, the sides of the slit moving away from each other and hence retreating, and the top of the instrument dilating slightly to allow the slit to open. Thus their behaviour is analogous with that of the human lips when blowing a horn or a trumpet.
The Lapp instrument, called fadno, was reported by Ernst Emsheimer, and was a stalk of angelica (a plant familiar to us as a green strip used on cakes) with around four fingerholes and a dilating reed. It seems to be unique to the Sami people living in that area with no parallel known elsewhere.
© Jeremy Montagu, 2018