This section is from the book "Commercial Gardening Vol2", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
A very large genus midway between the Aspidiums on one hand and the Nephrolepis and Polypodiums on the other. Representatives are to be found in all parts of the world, and are characterized by having a kidney-shaped indusium over the spore clusters, free or anastomosing veins, and fronds pinnate or compound. For market purposes the most important kinds are N, lepidum, a Brazilian species, having a tufted caudex and light-green pinnate fronds with serrated pinnules. N. patens, from the Tropics, has fronds 1-3 ft. long when mature, with deeply cut, lance-shaped pinnae. N. erythrosorum, from Japan and China, has ovate lance-shaped fronds 12-18 in. long, cut into lance-shaped pinnae. They are beautifully tinted with bronzy red when young, and are then very attractive and saleable. These three species are easily grown in a greenhouse, and like plenty of water. They sell best when grown in 5-in. pots, realizing from 6s. to 12s. per dozen.
Amongst hardy kinds the best known are N. Filix-mas, the "Male Buckler Fern", which has fronds 1-3 ft. long; N. dilatatum, the "Broad Buckler Fern"; N. Oreopteris, the "Mountain Buckler Fern"; N. Thelyp-teris, the "Marsh Buckler Fern"; and N. spinulosum. In the springtime quantities of the stems of these find their way to market and meet with a fairly ready sale.