Onoclea. FILICES. 499 



1. Onoclea sensibilis, Linn. (Plate CLX. var. obtusilohata.^ Sensitive Fern. 



Linn. sp. 2. p. 1062 ; Willd. sp. 5. p. 287 ; Michx. fl. 2. p. 272 ; " Schk. Fil. 1. 102 ;" 

 Pursh, fl. 2. p. 665 ; Bigel. fl. Bost. p. 391 ; Torr. compend. p. 384 ; Beck, hot. p. 448 ; 

 Darlingt. fl. Cest. p. 576. 



var. obtusilobata : fertile fern deeply bipinnati6d ; segmenis obovate, very obtuse ; the 

 margin slightly recurved. O. obtusilobata, Schk. Fil. t. 103?; Pursh, I. c. 



Stipe 8 - 12 inches long, somewhat angular, smooth except towards the base, where it is 

 a little chaffy. Sterile frond deeply pinnate, 8-12 inches long, triangular in the outline, 

 thin and delicate : segments an inch or more in breadth, obscurely serrulate on the margin ; 

 the lower ones toothed or often pinnatifid, and distinct at the base : veins beautifully anasto- 

 mosing, forming oblong areolas. Fertile frond 3-6 inches long, bipinnate ; the pinnae 1-2 

 inches long, and consisting of numerous triangular-globose distinct segments, which are dark 

 brown when ripe. In the variety obtusilobata, the frond is smaller, the segments of the 

 pinnae obovate, and the border only partially recurved or cucullate, so that they retain their 

 foliaceous character, and the sori are scarcely concealed ; thus exhibiting an intermediate form 

 between the barren and fertile fronds. 



Moist woods and thickets : common. Fr. July. The plant (which I once regarded as a 

 distinct species, but now consider an undoubted variety of O. sensibilis), is extremely rare, 

 and has hitherto been obtained in only three localities. It was first detected, many years 

 ago, by Dr. Jed. Smith, in Salem, Washington county ; and my drawing and engraving were 

 made from injured and imperfect specimens collected by him, before I knew the plant to be a 

 variety of the common species. Afterwards I saw it in the herbarium of Dr. Bigelow, who 

 collected it near Boston ; and lately it was found by Dr. Sartwell, in Yates county. Although 

 it is so different from the ordinary appearance of O. sensibilis, it is certainly a form of that 

 species ; for Dr. Sartwell found them growing together, and, in one instance at least, both 

 grew on the same root. Whether it i-s identical with the O. obtusilobata of Schkuhr, is 

 uncertain ; for Dr. Gray could not find the plant in that botanist's herbarium, nor in any other 

 European collection that he examined. Ragiopteris of Presl seems to have been founded 

 on the fertile frond of Onoclea, and the sterile frond of some other fern. 



14. WOODSIA. R. Br. in Linn, trans. 11. p. 173 ; Hook. gen. Fil. t. 119, and sp. Fil. 



p. 59. WOODSIA.. 



[Named in compliment to Josefb Woods, an English botanist.] 



Sori globose. Involucre more or less globose or cup-shaped, seated under the sorus and 

 sometimes completely enclosing it when young, finally bursting at the top ; the margin 

 irregularly lobed, or fringed with capillary segments. Capsules globose, on short stalks. — 

 Small cespitose ferns, with pinnated fronds. Veins forked ; the veinlets simple. 



63* 



