50 WOODSIA OBTUSA. COiMMON WOODSIA. 



tration grew, these barren fronds keep tolerably green till the 

 new ones come in spring, when they give way soon after the 

 appearance of the fertile fronds, and, later in the season, another 

 set of barren fronds appear. Our specimen was taken about 

 the end of May, and from this time to the end of October the 

 student may find along the Wissahickon excellent specimens for 

 study. In other parts of the country the plant does not seem to 

 be so highly favored. Mr. Williamson says, in his " Ferns of 

 Kentucky," " that in that State it grows in exposed situadons, 

 being better able to endure the direct rays of the sun than most 

 ferns. But in such places the pinnae are often very much 

 contracted, so that they seem to be crisp, and apparendy rolled 

 up." In Indiana also, according to a correspondent of the first 

 volume of the " Botanical Gazette," who writes from Hanover, it 

 dies away early in the season. He says : " Early in July, while 

 rambllne amongf some of the limestone cliff rocks of the Ohio 

 River, we secured our first specimens o{ Asplenhmi Ritta-mura- 

 via, in beautiful fruit; and since then we have visited the same 

 region every month in order to confirm our observations as to its 

 being an evergreen, and we are now fully convinced of the accu- 

 racy of our former remarks on this point. Associated with this 

 species and fruiting abundandy at the same time, we found quite 

 a growth of IVoodsia obtusa, but by the end of August it had 

 entirely v.nthered away. Its fruiting season begins here proba- 

 bly early in June." Other botanists seem to have very much lim- 

 ited the time when it may be found in fruit. Dr. Darlington in 

 his "Flora Cestrica" gives merely " July ; " as also does Professor 

 Asa Gray and Professor Wood, from whom our botanical 

 description is taken. They are probably referring to the time ot 

 the fruit's first appearance ; but for the benefit of those who are 

 making collecUons it is well to note how long it endures. 



Its botanical history has been varied. The knowledge of die 

 true character of ferns is of comparatively modern date. In the 

 time of Linnseus all the known North American ferns would be 

 referred to a very few genera, possibly only to Osnmnda. Pte7ds, 



