BLECHNUM. A huge group of ferns, nearly spanning the globe. Most of those in cultivation, both temperate and tropical, have thick, evergreen sterile (vegetative) fronds resembling those of the polypodies and distinct fertile (sporing) fronds. They have several different uses according to the habit of the plants. The following are best in shade, with acid, well drained soil and constant moisture (though they actually use little water).
penna-marina. An interesting little fern, attractive as a ground cover. It has a creeping rhizome, which branches to form a leafy mat. The fronds are short (6" or less in this form), thick and dark and shiny. Older fronds are dark green, while the new shoots are tinted with bronze. Probably hardy to 15oF or less.