668 FILICES. (FERNS.) 



necklace-shaped pinnae, the lowest ones much smaller. (S. Pennsylvania, 

 Willd. Onoclea Struthiopteris, L., Hook.) Alluvial soil : not rare northward. 



Fronds intermediate between the sterile and fertile condition (bearing a few 

 fruit-dots on contracted, but still herbaceous pinna) are sometimes found; a 

 condition analogous to the var. obtusiloba of Onoclea sensibilis. (Eu.) 



15. ONOCLEA, L. SENSITIVE FERN. (PI. 18.) 



Fertile frond twice pinnate, much contracted ; the pinnules short and revolute, 

 usually so rolled up as to be converted into berry-shaped closed involucres, filled 

 with sporangia, and forming a one-sided spike or raceme. Fruit-dots one on 

 the middle of each strong and simple primary vein (with or without sterile cross- 

 veins), round, soon all confluent. Indusium very thin, hood-like, lateral, fixed 

 by its lower side, free on the upper (towards the apex of the pinnule). Sterile 

 fronds rising separately from the naked extensively creeping rootstock, long- 

 stalked, broadly triangular in outline, deeply pinnatifid into lance-oblong pinnae, 

 which are entire or wavy-toothed, or the lowest pair sinuate-pinnatifid (decaying 

 in autumn) ; veins reticulated with fine meshes. (Name apparently from ovos, 

 a vessel, and /cXei'co, to dose, from the singularly rolled up fructification.) 



1. O. sensibilis, L. Moist or wet places, along streams: common. 

 July. A rare abnormal state, in which the pinnas 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, is the var. 

 OBTUSILOBA.TA, Torr., N. Y. State Fl. (Connecticut, New York, &c.) This 

 explains the long-lost 0. obtusilobata, Schkuhr (from Pennsylvania), which, as 

 figured, has the sterile fronds thus 2-pin nately divided. (Ragiopteris, PresL, is 

 founded on a young fertile frond of this species with the sterile frond of some 

 Aspidium.) 



16. WO6DSIA, R. Brown. WOODSIA. (PI. 18.) 



Fruit-dots round, borne on the back of simply-forked free veins ; the very thin 

 and often evanescent indusium attached by its base all around the receptacle, 

 under the sporangia, either small and open, or else early bursting at the top into 

 irregular pieces or lobes. Small and tufted pinnately-divided Ferns. (Dedi- 

 cated to Joseph Woods, an English botanist.) 



1 . HYPOPELTIS, Torr. Indusium conspicuous, at first enclosing the sporangia, 



but early opening at the top, and splitting into several spreading jagged lobes. 

 1. W. Obttisa, Torr. Frond broadly lanceolate, minutely glandular-hairy 

 (6' -12' high), pinnate, or nearly twice-pinnate; pinnae rather remote, triangu- 

 lar-ovate or oblong (l'-2' long), bluntish, pinnately parted; segments oblong, 

 obtuse, crenately toothed, the lower ones pinnatifid with toothed lobes ; veins 

 forked, and bearing the fruit-dots on or below the minutely toothed lobes. 

 W. Perriniana, Hook. $ Grev. Aspidium obtusum, Weber $ Mohr., Willd.) 



Rocky banks and cliffs : common, especially westward. July. 



2. WOODSIA proper. Indusium minute or evanescent, open and fiat from an 

 early stage, and concealed under the fruit-dot, its margin deft into slender hairs or 

 cilia. 



