"Pencil Cactus" or "Milk Bush" Narrow rounded much-forked stems rapidly grow to form a tree. Used in Tanzania to cure sexual impotence and as a mosquito repellent. (We will not refund for this if, after a year, your child support payments increase dramatically.) Very toxic sap--be sure never to get any sap near your eyes. Still one of the best for a long time specimen houseplant in a sunny window free of children--we know of several situated in low humidity professional offices with little care (but next to a big southern window) that have become magnificent plants over the years.