A small genus of Ferns remarkable for their distinct appearance and for having the spore clusters borne on separate fronds. The "Flowering Fern" or "Royal Fern" (0. regalis) is the best-known species, and is found in many parts of the temperate and subtropical regions. It grows from 6-8 ft. high, having twice-pinnate barren fronds, and erect cylindrical trusses of fertile fronds thrown up in the centre. Small plants in 3-in. or 5-in. pots sell well, and are easily grown in a cool house. The variety palustris requires more humid conditions, and the variety corymbifera is a rare crested form. 0. Hilli is more compact in growth, but is a fine plant. 0. javanica, a native of Java and Ceylon, is of slower growth than the others, and is somewhat stiffer in appearance.