OSMUNDA, a genus of ferns popularly known as flowering ferns. With one other genus they form the suborder Osmundaceæ, in which the spore cases are naked, globose, and each with a short pedicel or stalk; their surface is covered with a fine network, and they open into halves by a longitudinal slit. The name flowering fern is of course a misnomer, and was probably given on account of the showy character of the fructification. They are the largest and most conspicuous of our native ferns, and are abundant in low grounds almost everywhere, north and south, forming large clumps; each rootstock throws up numerous fronds, which are often 5 ft. high. We have three species. The royal fern, O. regalis, differs from the others in having twice-pinnate fronds, which bear the fructification at the top, where it forms a showy panicle. This species is also found in Europe, where it attains a much greater size than with us; here it is rarely over 5 ft. high, but in favorable situations in England it not unfrequently grows to 8 or 10 ft., and specimens as high as 11 ft. have been found. The other two species have their sterile fronds once pinnate. Clayton's flowering fern (O. Claytoniana) rarely exceeds 3 ft.; from two to five pairs of the divisions in the middle of the frond are fertile, and being covered with spore cases have a very different appearance from the rest of the frond. The third species is the cinnamon fern (O. cinnamomea), which differs from the others in having some of its fronds entirely fertile and the others, from the same rootstock, entirely sterile. This is very common in swamps and wet places, and in early spring the unfolding sterile fronds, clothed with a rusty wool, are conspicuous; they become smooth when full-grown; the fertile fronds are in the centre, 1 to 2 ft. long, and covered with bright cinnamon-colored spore cases; these decay early, and the sterile fronds grow to a length of 4 or 5 ft.
Royal Fern (Osmunda regalis).