Onoclea
(changed from the Greek name of a plant, Onokleion, or from onos, a vessel, and kleio, to close; alluding to the singularly rolled-up fructification). Including Struthiopteris. ORD. Filices. A small genus (three species) of hardy Ferns, inhabiting cold and temperate regions. Sori dorsal, globose, on the veins of the changed and contracted pinnae of the fertile fronds, and quite concealed by their revolute margins; involucre very thin, delicate-membranous, hemispherical or half cup-shaped, originating from the inferior side of the sorus, or wanting. The species thrive best in a good, strong, loamy soil, and are very suitable for the outdoor fernery. For general culture, see Ferns.
O. germanica (German).* Ostrich Fern. fronds broad-lanceolate, long-attenuated at the base; fertile pinnae short, much contracted, linear-terete, torulose, lobed and torn at the margin; involucre cup-shaped, very fragile, and soon obsolete. Northern hemisphere. A handsome species. SYNS. Struthiopteris germanica, S. pennsylvanica.
O. orientalis (Eastern). fronds ovateoblong, not attenuated at the base; fertile ones oblong, often 2ft. long, contracted; pinnae linear-oblong, flattened, two-edged, the broad, refracted margins covering the whole back, dark purple-brown, glossy, at length spreading, torn at the margin. Sikkim, Japan. SYN. Struthiopteris orientalis.
O. sensibilis (sensitive).* Rootstock extensively creeping. fertile fronds bipinnate; pinnules recurvate, globose. sterile fronds rising separately from the naked rootstock, long-stalked, broadly triangular in outline, deeply pinnatifid into lanceolateo-blong pinnae, which are entire or wavy-toothed; involucre a globose pellicle, bursting at the summit. North America, North Asia, 1799.
O. s. obtusilobata (obtuse-lobed). A rare abnormal form, in which the pinnae of some of the sterile fronds, becoming again pinnatifid, and more or less contracted, bear some fruit-dots without being much revolute, or losing their foliaceous character. Pennsylvania.