GG8 FiLiCES. (ferns.) 



Jiv'cklacc-sliapcd pinna?, tlic lowest ones much smaller. (S. Pcnnsylvanica, 

 Wi/hl. Onoclea Stnitiiioptcris, L., Ilook.) — Alluvial soil : not rare northward. 



— Fronds intermediate between the sterile and fertile eondition (bearing a few 

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

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



15. ONOCLEA, L. Sensitive Fern. (PI. 18.) 



Fertile frond twice pinnate, much eontracted ; 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 raccmj. Fruit-dots one on 

 the middle of each strong and simple ])rimary vein (with or without sterile cross- 

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

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

 fronds ri.sing separately from the naked extensively creeping rootstock, long- 

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

 ■\vhich arc entire or wavy-toothed, or the lowest pair sinuate-pinnatifid (decaying 

 in autumn) ; veins reticulated with line meshes. (Name apparently from wos, 

 a vessel, and (cXfio), to close, 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 pinna; 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. 

 OBTUSiLOiiXxA, Torr., N. Y. Slate Fl. (Connecticut, New York, &.c.) This 

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

 figured, has the sterile fronds thus 2-pinnately divided. (Ragiopteris, PrcsL, is 

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

 Aspidium.) 



16. WOODSIA, R. r>rown. 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. — RnuvU and tufted pinnatcly-divided Ferns. (Dedi- 

 cated to Joseph Woods, an English botanist.) 



§ 1. HYPOPELTIS, Torr. Indusium consplcnous, at Jirst enclosing the sjm-angia, 

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



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

 (C'-12' high), pinnate, or nearly twice-pinnate; pinna; rather remote, triangu- 

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

 obtuse, crcnately 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, c^- Grcv. Aspidium obtusum, Wtbcr <j- Mohr., Willd.) 



— Rocky banks and clifis : common, especially westward. July. 



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

 early stage, and concealed under thefruit-dot, its margin cle/l into slender hairs or 

 cilia- 



