26 MAKSH FERN. 



fern only in the pinnules being somewhat smaller and 

 narrower, and a trifle curved forward in their margins, 

 so as to present a prickly-looking surface, like that of 

 holly. 



MARSH FERN. 



ASPIDIUM THELYPTERIS. 



[Swartz, /Smith, Hooker, Hentkam.] 

 (Fig. 2.) 



SYNONYMS. 



LASTKEA THELYPTERIS. Babington, Presl, Moore. 

 HEMESTHEUM THELYPTERIS. Newman. 



THIS fern has been described by botanists under 

 the generic names of Polypodium, Acrosticum, Las- 

 trea, and Polystichum, but has always retained its 

 specific name, Thelypteris. It has a short creeping 

 root-stock, with single (not tufted) erect fronds, 

 which are bipinnate and without glands. The fronds 

 are of two kinds, barren and fertile ; the former 

 appear in May, the latter in July. The pinnules of 

 the young frond stand out at right angles with the 

 stem. The fertile fronds are much taller than the 

 barren ones, sometimes attaining a height of three 

 feet. The indusium covering the spore-cases is thin, 

 and soon thrown off and lost. 



This fern delights in marshy, boggy lands, and is 



