Microsorum Pteropus "Narrow Leaf", also commonly known as Java Fern Narrow Leaf, is a cross between Regular Java Fern and Java Fern Needle Leaf. Ideally, it should be attached to rock or wood. If planted in a substrate, do not cover the rhizome because it will rot. It is easy to propagate by splitting the horizontal rhizome. Like other Java Fern species, it is a hardy plant that grows in all conditions and is a very popular beginner plant. The black spots under the leaves are sporangia (reproductive organs), not signs of disease, as many believe.