BRITISH FERNS. 41 



specimens of Polypodium Lonchitis in the Linnean Herbarium, 

 and I am totally unable to detect any difference between them ; 

 I am therefore of the opinion that had the plant from which 

 these fronds were gathered been transplanted to a hedge-row 

 in which its roots could reach abundance of decaying wood, that 

 it would speedily have become broken into lobatum, and before 

 many years into angulare. 



Although our botanists have named four forms of this 

 fern, I believe there are but three which will be generally 

 understood; all these I would consider as constituting but a 

 single species, to which I would assign the Linnean name of 

 aculeatum, and call the different forms merely varieties, 

 thus : 



Var. 1. Angular type. Frond doubly pinnate; pinnulae 

 ovate, bluntish, stalked and auricled at the base; the whole 

 plant light, feathery, graceful, and extremely flexible : this form 

 is figured at page 37. 



Var. 2. Lobate type. Frond doubly pinnate ; pinnulse 

 pointed, decurrent, serrated, the foremost of the lower pair on 

 each pinna very large and pointing towards the apex of the 

 frond ; the whole plant rigid, heavy, compact, and unbending ; 

 grows in general horizontally : this form is figured at page 39. 



Var. 3. Lonchitiform type. Frond simply pinnate ; pinnae 

 stalked, undivided, prickly; habit weak, flexible, pendulous: 

 this form is figured at page 40. 



Mr. Francis has figured all the varieties of this plant as having 

 the reniform fructification of the genus Lastraea. Fig. 1, 2, and 4, 

 plate 2, belong to the lobate type of the above list ; figs. 1 and 4 

 correspond with my figure f; figs. 3 and 5 of Francis belong to 

 the angular type. 



As many of our botanists will be inclined to smile at my 

 attempt to blend together species which they have been accus- 

 tomed to consider as perfectly distinct, I will mention that since 

 the publication of my remarks in the Magazine of Natural 

 History, I have received various written communications on the 

 subject, some of them from botanists who in some degree 

 participate in my views ; for instance, the following from Mr. 

 C. C. Babington. " I am inclined to consider lobatum, 

 aculeatum, and angulare, as forms of one species ; many inter- 

 mediate states occur in which it is quite impossible to say to 

 which of the supposed species they ought to be referred ; some 



