According to Wikipedia, the wood density of a floss silk is 0.27 g/cm^3. Though no dimensions are given, figuring the club to be about 1 m long and 5 cm in diameter based on the pictures, and figuring it to be a cylinder, would give it a weight of 0.27*100*2.5^2*pi = 530 g, agreeing with fearn rather light for a club, yes? Of course, if poison is used all bets are off, and if Tim's suggestion that it may be South American is true, the natives there do certainly use poisons on their darts. Of course, they do in the Phillipines too I think. Dimensions, weight, and a picture of the cross section WOULD certainly help. I was unable to find a wood density for young spiny rattan...