84 iiE. ciincn o>" the roEii or the 



can confirm the general accuracy of Duval-Jouve'a figures so far 

 as they relate to species found in Britain. 



To discuss the difficult question of the nomenclature of these 

 plants is beside my purpose ; I shaU therefore do no more than 

 designate each form named by two or three of its best-known 

 synonyms. At the same time, it seems that the results of such 

 inquiries as the present, as possibly affording criteria of generic if 

 not of sjjccific difference, cannot be wholly disregarded, and may 

 ultimately aid us in arriving at a more consistent classification 

 for the FUices. 



The genera Foli/stichum and Lastrea as understood by Moore 

 and many other authors are respectively coextensive (so far as 

 our native ferns are concerned) with the genera Aspidium and 

 Nephrodium adopted by Hooker in his 'British Ferns' (1862). 

 I have examined transverse sections of the stipes of all the gene- 

 rally received species and many of the varieties included under 

 these generic ai)pellations, and in two species only did I find any 

 material departure from tliat one particular arrangement of the 

 vascular fasciculi which is disclosed by a transverse stipital section 

 of such a form as IMoore's Lastrea Filix-mas or Polystichmn Lon- 

 cJiUis. In Nephrodium Filix-mas, N. rigidum, N. cristatum, I^. 

 spinulosum a. tipinnatum, (3. dilatatum, y. cdmulum, i. dwmeforum, 

 Aspidium aciileatum a. lohatum, (i. infermeditim, y. angulare of 

 Hooker, and also in the forms Lopliodium glandulosum, L. uligi- 

 nosum, L. nanum, and L. collinum of Newman, the same disposi- 

 tion of the vascular tissue occurs. The two notable exceptions to 

 which I have before alluded are found in Neplirodiwm Thelypteris 

 and N. Ormpferis of Hooker, identical with tbo Lastrea Thely- 

 pteris and L. montana of Moore and the ILemestheum Thelypteris 

 and Lastrea (JlemestJieum) montana of Newman. In fig. 1 the 

 prevalent arrangement is shown ; in fig. 2 that wbicb occurs in 

 the mountain fern ; while fig. 3 represents that of the marsh fern, 

 which I will now more particularly describe. In all cases the 

 sections noticed are those of tlie stipes, not of the stem ; and I 

 have freely availed myself of the use of a very weak solution of 

 perchloride of iron, in order that the tracts containing tannin 

 might be distinctly marked out. 



Nephrodium Thelypteris, Hooker. 

 Hemestlieiim Thelypteris, Newman. 

 Lastrea Thelypteris, Moore. 



The present plaut is not only closely connected in many of its 



