Juncus effusus or more commonly called, soft rush. Did you know that in old days, the insides of the plant was used as wicks? It is true, and quite possible. If you take its smooth cylinder stem and carefully peek off the green coat, you will be able to press out with your nail (that’s how I do it) a white woolen string that can be lit. Although you have to be rather sleight. Because not only does it break during the peel, it is so fragile that it usually breaks when you dip it in stearin. Yet, if you happen to succeed, you will get an extraordinary candle – especially if you reuse clean stearin from old candles. I have not yet been able to make a candle from a common rush. It usually breaks for me. Maybe you will have better luck?